Method and apparatus for transmitting and receiving signal in wireless communication system

ABSTRACT

Provided are a method of transmitting and receiving a signal in a wireless communication system, and an apparatus supporting the same.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. application Ser. No.16/930,858, filed on Jul. 16, 2020, which is a continuation ofInternational Application No. PCT/KR2020/000520, filed on Jan. 10, 2020,which claims priority under 35 U.S.C. 119(a) to Korean PatentApplication Nos. 10-2019-0003992, filed on Jan. 11, 2019,10-2019-0018232, filed on Feb. 15, 2019, 10-2019-0035512, filed on Mar.28, 2019, and 10-2019-0051919, filed on May 3, 2019, which are herebyincorporated by reference herein in their entirety.

TECHNICAL FIELD

Various embodiments of the present disclosure relate to a wirelesscommunication system, and more particularly, to a method and apparatusfor transmitting and receiving a signal in a wireless communicationsystem.

BACKGROUND

Wireless access systems have been widely deployed to provide varioustypes of communication services such as voice or data. In general, awireless access system is a multiple access system that supportscommunication of multiple users by sharing available system resources (abandwidth, transmission power, etc.) among them. For example, multipleaccess systems include a code division multiple access (CDMA) system, afrequency division multiple access (FDMA) system, a time divisionmultiple access (TDMA) system, an orthogonal frequency division multipleaccess (OFDMA) system, and a single carrier frequency division multipleaccess (SC-FDMA) system.

As a number of communication devices have required higher communicationcapacity, the necessity of the mobile broadband communication muchimproved than the existing radio access technology (RAT) has increased.In addition, massive machine type communications (MTC) capable ofproviding various services at anytime and anywhere by connecting anumber of devices or things to each other has been considered in thenext generation communication system. Moreover, a communication systemdesign capable of supporting services/UEs sensitive to reliability andlatency has been discussed.

As described above, the introduction of the next generation RATconsidering the enhanced mobile broadband communication, massive MTC,ultra-reliable and low latency communication (URLLC), and the like hasbeen discussed.

SUMMARY

Various embodiments of the present disclosure may provide a method andapparatus for transmitting and receiving a signal in a wirelesscommunication system.

For example, various embodiments of the present disclosure may provide amethod and apparatus for transmitting and receiving an initial signalincluding information related to transmission of a transmission burst ina wireless communication system.

For example, various embodiments of the present disclosure may provide amethod and apparatus for transmitting and receiving a physical downlinkcontrol channel (PDCCH) based on search space set switching in awireless communication system.

For example, various embodiments of the present disclosure may provide amethod and apparatus for performing cross-carrier scheduling (CCS) in awireless communication system.

It will be appreciated by persons skilled in the art that the objectsthat could be achieved with the present disclosure are not limited towhat has been particularly described hereinabove and the above and otherobjects that the present disclosure could achieve will be more clearlyunderstood from the following detailed description.

Various embodiments of the present disclosure may provide a method andapparatus for transmitting and receiving a signal in a wirelesscommunication system.

According to various embodiments of the present disclosure, a method ofan apparatus in a wireless communication system may be provided.

In an exemplary embodiment, the method may includes obtaininginformation regarding groups for at least one search space set relatedto physical downlink control channel (PDCCH) monitoring; and performing,based on the information regarding the groups, the PDCCH monitoringaccording to a search space set related to a second group among thegroups.

In an exemplary embodiment, after at least one predetermined conditionis satisfied:

(i) after a first predetermined time, PDCCH monitoring according to asearch space set related to a first group different from the secondgroup among the groups may be started, and (ii) the PDCCH monitoringaccording to the search space set related to the second group may beended.

In an exemplary embodiment, the first predetermined time may beconfigured as at least one symbol.

In an exemplary embodiment, the first predetermined time may bedetermined to be equal to or longer than a processing time.

In an exemplary embodiment, the processing time may be a time requiredfor the apparatus to perform search space set switching based onstarting the PDCCH monitoring according to the search space set relatedto the first group and ending the PDCCH monitoring according to thesearch space set related to the second group.

In an exemplary embodiment, the PDCCH monitoring according to the searchspace set related to the first group may be started in a 1^(st) slotafter the first predetermined time.

In an exemplary embodiment, the predetermined conditions may include:(i) a first condition including information related to a channeloccupancy time (COT) being indicated by downlink control information(DCI) carried by a group-common PDCCH (GC-PDCCH); (ii) a secondcondition including starting the PDCCH monitoring according to thesearch space set related to the first group and ending the PDCCHmonitoring according to the search space set related to the second groupbeing indicated by a predetermined information field in the DCI carriedby the GC-PDCCH; and (iii) a third condition including the PDCCHmonitoring according to the search space set related to the second groupbeing configured to be performed during a second predetermined time, andthe second predetermined time being expired.

In an exemplary embodiment, the search space sets may be configured inan unlicensed band, the DCI may further indicate information related toa occupied frequency resource in the unlicensed band, a size of thefrequency resource may be an N multiple size of a frequency unit forperforming a channel access procedure (CAP) for the unlicensed band, andN may be a natural number.

In an exemplary embodiment, the search space set related to the firstgroup may be located outside of the COT in a time domain, and the searchspace set related to the second group may be located inside of the COTin the time domain.

In an exemplary embodiment, the search space set related to the firstgroup may be periodically configured based on a first periodicity in thetime domain, and the search space set related to the second group may beperiodically configured in the time domain based on a second periodicitydifferent from the first periodicity.

In an exemplary embodiment, the information regarding the groups may beobtained based on a higher layer signaling.

According to various embodiments of the present disclosure, an apparatusoperating in a wireless communication system may be provided.

In an exemplary embodiment, the apparatus may include a memory, and atleast one processor coupled with the memory.

In an exemplary embodiment, the at least one processor may be configuredto obtain information regarding groups for at least one search space setrelated to physical downlink control channel (PDCCH) monitoring; andperform, based on the information regarding the groups, the PDCCHmonitoring according to a search space set related to a second groupamong the groups.

In an exemplary embodiment, after at least one predetermined conditionsis satisfied: (i) after a first predetermined time, PDCCH monitoringaccording to a search space set related to a first group different fromthe second group among the groups may be started, and (ii) the PDCCHmonitoring according to the search space set related to the second groupmay be ended.

In an exemplary embodiment, the apparatus may be configured tocommunicate with at least one of a mobile terminal, a network, or anautonomous driving vehicle other than a vehicle including the apparatus.

According to various embodiments of the present disclosure, a method ofan apparatus in a wireless communication system may be provided.

In an exemplary embodiment, the method may include transmittinginformation regarding groups for at least one search space set relatedto physical downlink control channel (PDCCH) monitoring; andtransmitting a PDCCH according to a search space set related to a secondgroup among the groups.

In an exemplary embodiment, after at least one predetermined conditionis satisfied: (i) after a first predetermined time, PDCCH transmissionaccording to a search space set related to a first group different fromthe second group among the groups may be started, and (ii) the PDCCHtransmission according to the search space set related to the secondgroup may be ended.

According to various embodiments of the present disclosure, an apparatusoperating in a wireless communication system may be provided.

In an exemplary embodiment, the apparatus may include a memory and atleast one processor coupled with the memory.

In an exemplary embodiment, the at least one processor may be configuredto transmit information regarding groups for at least one search spaceset related to physical downlink control channel (PDCCH) monitoring; andtransmit a PDCCH according to a search space set related to a secondgroup among the groups.

In an exemplary embodiment, after at least one predetermined conditionis satisfied: (i) after a first predetermined time, PDCCH transmissionaccording to a search space set related to a first group different fromthe second group among the groups may be started, and (ii) the PDCCHtransmission according to the search space set related to the secondgroup may be ended.

According to various embodiments of the present disclosure, an apparatusoperating in a wireless communication system may be provided.

In an exemplary embodiment, the apparatus may include at least oneprocessor, and at least one memory storing at least one instructioncausing the at least one processor to perform a method.

In an exemplary embodiment, the method may includes obtaininginformation regarding groups for at least one search space set relatedto physical downlink control channel (PDCCH) monitoring; and performing,based on the information regarding the groups, the PDCCH monitoringaccording to a search space set related to a second group among thegroups.

In an exemplary embodiment, after at least one predetermined conditionsis satisfied: (i) after a first predetermined time, PDCCH monitoringaccording to a search space set related to a first group different fromthe second group among the groups may be started, and (ii) the PDCCHmonitoring according to the search space set related to the second groupmay be ended.

According to various embodiments of the present disclosure, aprocessor-readable medium storing at least one instruction causing atleast one processor to perform a method may be provided.

In an exemplary embodiment, the method may includes obtaininginformation regarding groups for at least one search space set relatedto physical downlink control channel (PDCCH) monitoring; and performing,based on the information regarding the groups, the PDCCH monitoringaccording to a search space set related to a second group among thegroups.

In an exemplary embodiment, after at least one predetermined conditionsis satisfied: (i) after a first predetermined time, PDCCH monitoringaccording to a search space set related to a first group different fromthe second group among the groups may be started, and (ii) the PDCCHmonitoring according to the search space set related to the second groupmay be ended.

Various embodiments of the present disclosure as described above areonly some of preferred embodiments of the present disclosure, and thoseskilled in the art may derive and understand many embodiments in whichtechnical features of the various embodiments of the present disclosureare reflected based on the following detailed description.

According to various embodiments of the present disclosure, thefollowing effects may be achieved.

According to various embodiments of the present disclosure, a method andapparatus for transmitting and receiving a signal in a wirelesscommunication system may be provided.

Further, according to various embodiments of the present disclosure, auser equipment (UE) may be aware of the presence of an opportunisticbase station (BS) transmission after success of a channel accessprocedure (CAP), based on an initial signal and accordingly receive aphysical downlink control channel (PDCCH) and/or a physical downlinkshared channel (PDSCH) and/or measure channel state information (CSI).

Further, according to various embodiments of the present disclosure,power consumption of a UE for PDCCH monitoring within a channeloccupancy time (COT) of a BS may be reduced.

Further, according to various embodiments of the present disclosure, theprobability of succeeding in downlink control information (DCI)transmission and reception may be increased.

It will be appreciated by persons skilled in the art that the effectsthat can be achieved with the present disclosure are not limited to whathas been particularly described hereinabove and other advantages of thepresent disclosure will be more clearly understood from the followingdetailed description taken in conjunction with the accompanyingdrawings.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings, which are included to provide a furtherunderstanding of the disclosure and are incorporated in and constitute apart of this application, illustrate embodiments of the disclosure andtogether with the description serve to explain the principle of thedisclosure. In the drawings:

FIG. 1 is a diagram illustrating physical channels and a signaltransmission method using the physical channels, which may be used invarious embodiments of the present disclosure;

FIGS. 2A and 2B are diagrams illustrating a radio frame structure in along term evolution (LTE) system to which various embodiments of thepresent disclosure are applicable;

FIG. 3 is a diagram illustrating a radio frame structure in an LTEsystem to which various embodiments of the present disclosure areapplicable;

FIG. 4 is a diagram illustrating a slot structure in an LTE system towhich various embodiments of the present disclosure are applicable;

FIG. 5 is a diagram illustrating an uplink (UL) subframe structure in anLTE system to which various embodiments of the present disclosure areapplicable;

FIG. 6 is a diagram illustrating a downlink (DL) subframe structure inan LTE system to which various embodiments of the present disclosure areapplicable;

FIG. 7 is a diagram illustrating a radio frame structure in a new radioaccess technology (NR) system to which various embodiments of thepresent disclosure are applicable;

FIG. 8 is a diagram illustrating a slot structure in an NR system towhich various embodiments of the present disclosure are applicable;

FIG. 9 is a diagram illustrating a self-contained slot structure towhich various embodiments of the present disclosure are applicable;

FIG. 10 is a diagram illustrating the structure of one resource elementgroup (REG) in an NR system to which various embodiments of the presentdisclosure are applicable;

FIGS. 11A and 11B are diagrams illustrating exemplary control channelelement (CCE)-to-resource element group (REG) mapping types according tovarious embodiments of the present disclosure;

FIG. 12 is a diagram illustrating an exemplary block interleaveraccording to various embodiments of the present disclosure;

FIGS. 13A to 13C are diagrams illustrating exemplary slot formatsaccording to various embodiments of the present disclosure;

FIGS. 14A and 14B are diagrams illustrating exemplary resource sharingfor enhanced mobile broadband (eMBB) transmission and ultra-reliable andlow latency communications (URLLC) transmission according to variousembodiments of the present disclosure;

FIG. 15 is a diagram illustrating an exemplary DL preemption indicationaccording to various embodiments of the present disclosure;

FIG. 16 is a diagram illustrating an exemplary preemption operationaccording to various embodiments of the present disclosure;

FIGS. 17A and 17B are diagrams illustrating an exemplary method ofrepresenting preemption indication information in a bitmap according tovarious embodiments of the present disclosure;

FIG. 18 is a diagram illustrating exemplary multiplexing between shortand long PUCCHs and a UL signal according to various embodiments of thepresent disclosure;

FIGS. 19A and 19B are diagrams illustrating an exemplary wirelesscommunication system supporting an unlicensed band to which variousembodiments of the present disclosure are applicable;

FIG. 20 is a flowchart illustrating a DL channel access procedure (CAP)for transmission in an unlicensed band, to which various embodiments ofthe present disclosure are applicable;

FIG. 21 is a flowchart illustrating a UL CAP for transmission in anunlicensed band, to which various embodiments of the present disclosureare applicable;

FIG. 22 is a diagram illustrating an exemplary structure of transmittingand receiving an initial signal according to various embodiments of thepresent disclosure;

FIG. 23 is a diagram illustrating a signal flow for an exemplary methodof transmitting and receiving an initial signal according to variousembodiments of the present disclosure;

FIG. 24 is a diagram illustrating an exemplary physical downlink controlsignal (PDCCH) transmission and reception structure according to variousembodiments of the present disclosure;

FIG. 25 is a diagram illustrating an exemplary PDCCH transmission andreception structure according to various embodiments of the presentdisclosure;

FIG. 26 is a diagram illustrating an exemplary PDCCH transmission andreception structure according to various embodiments of the presentdisclosure;

FIG. 27 is a diagram illustrating a signal flow for an exemplary methodof transmitting and receiving a PDCCH according to various embodimentsof the present disclosure;

FIG. 28 is a diagram illustrating a signal flow for an exemplaryscheduling method according to various embodiments of the presentdisclosure;

FIG. 29 is a simplified diagram illustrating a signal flow for anexemplary method of operating a user equipment (UE) and a base station(BS) according to various embodiments of the present disclosure;

FIG. 30 is a flowchart illustrating a method of operating a UE accordingto various embodiments of the present disclosure;

FIG. 31 is a flowchart illustrating a method of operating a BS accordingto various embodiments of the present disclosure;

FIG. 32 is a block diagram illustrating an apparatus for implementingvarious embodiments of the present disclosure;

FIG. 33 is a diagram illustrating a communication system to whichvarious embodiments of the present disclosure are applicable;

FIG. 34 is a block diagram illustrating wireless devices to whichvarious embodiments of the present disclosure are applicable;

FIG. 35 is a block diagram illustrating another example of wirelessdevices to which various embodiments of the present disclosure areapplicable;

FIG. 36 is a block diagram illustrating a portable device applied tovarious embodiments of the present disclosure;

FIG. 37 is a block diagram illustrating a vehicle or an autonomousdriving vehicle, which is applied to various embodiments of the presentdisclosure; and

FIG. 38 is a block diagram illustrating a vehicle applied to variousembodiments of the present disclosure.

DETAILED DESCRIPTION

The various embodiments of the present disclosure described below arecombinations of elements and features of the various embodiments of thepresent disclosure in specific forms. The elements or features may beconsidered selective unless otherwise mentioned. Each element or featuremay be practiced without being combined with other elements or features.Further, various embodiments of the present disclosure may beconstructed by combining parts of the elements and/or features.Operation orders described in various embodiments of the presentdisclosure may be rearranged. Some constructions or elements of any oneembodiment may be included in another embodiment and may be replacedwith corresponding constructions or features of another embodiment.

In the description of the attached drawings, a detailed description ofknown procedures or steps of the various embodiments of the presentdisclosure will be avoided lest it should obscure the subject matter ofthe various embodiments of the present disclosure. In addition,procedures or steps that could be understood to those skilled in the artwill not be described either.

Throughout the specification, when a certain portion “includes” or“comprises” a certain component, this indicates that other componentsare not excluded and may be further included unless otherwise noted. Theterms “unit”, “-or/er” and “module” described in the specificationindicate a unit for processing at least one function or operation, whichmay be implemented by hardware, software or a combination thereof. Inaddition, the terms “a or an”, “one”, “the” etc. may include a singularrepresentation and a plural representation in the context of the variousembodiments of the present disclosure (more particularly, in the contextof the following claims) unless indicated otherwise in the specificationor unless context clearly indicates otherwise.

In the various embodiments of the present disclosure, a description ismainly made of a data transmission and reception relationship between aBase Station (BS) and a User Equipment (UE). A BS refers to a terminalnode of a network, which directly communicates with a UE. A specificoperation described as being performed by the BS may be performed by anupper node of the BS.

Namely, it is apparent that, in a network comprised of a plurality ofnetwork nodes including a BS, various operations performed forcommunication with a UE may be performed by the BS, or network nodesother than the BS. The term ‘BS’ may be replaced with a fixed station, aNode B, an evolved Node B (eNode B or eNB), gNode B (gNB), an advancedbase station (ABS), an access point, etc.

In the various embodiments of the present disclosure, the term terminalmay be replaced with a UE, a mobile station (MS), a subscriber station(SS), a mobile subscriber station (MSS), a mobile terminal, an advancedmobile station (AMS), etc.

A transmission end is a fixed and/or mobile node that provides a dataservice or a voice service and a reception end is a fixed and/or mobilenode that receives a data service or a voice service. Therefore, a UEmay serve as a transmission end and a BS may serve as a reception end,on an uplink (UL). Likewise, the UE may serve as a reception end and theBS may serve as a transmission end, on a downlink (DL).

The various embodiments of the present disclosure may be supported bystandard specifications disclosed for at least one of wireless accesssystems including an institute of electrical and electronics engineers(IEEE) 802.xx system, a 3rd generation partnership project (3GPP)system, a 3GPP long term evolution (LTE) system, 3GPP 5G NR system and a3GPP2 system. In particular, the various embodiments of the presentdisclosure may be supported by the standard specifications, 3GPP TS36.211, 3GPP TS 36.212, 3GPP TS 36.213, 3GPP TS 36.321, 3GPP TS 36.331,3GPP TS 37.213, 3GPP TS 38.211, 3GPP TS 38.212, 3GPP TS 38.213, 3GPP TS38.321 and 3GPP TS 38.331. That is, the steps or parts, which are notdescribed to clearly reveal the technical idea of the variousembodiments of the present disclosure, in the various embodiments of thepresent disclosure may be explained by the above standardspecifications. All terms used in the various embodiments of the presentdisclosure may be explained by the standard specifications.

Reference will now be made in detail to the various embodiments of thepresent disclosure with reference to the accompanying drawings. Thedetailed description, which will be given below with reference to theaccompanying drawings, is intended to explain exemplary embodiments ofthe present disclosure, rather than to show the only embodiments thatcan be implemented according to the disclosure.

The following detailed description includes specific terms in order toprovide a thorough understanding of the various embodiments of thepresent disclosure. However, it will be apparent to those skilled in theart that the specific terms may be replaced with other terms withoutdeparting the technical spirit and scope of the various embodiments ofthe present disclosure.

Hereinafter, 3GPP LTE/LTE-A systems and 3GPP NR system are explained,which are examples of wireless access systems.

The various embodiments of the present disclosure can be applied tovarious wireless access systems such as code division multiple access(CDMA), frequency division multiple access (FDMA), time divisionmultiple access (TDMA), orthogonal frequency division multiple access(OFDMA), single carrier frequency division multiple access (SC-FDMA),etc.

CDMA may be implemented as a radio technology such as universalterrestrial radio access (UTRA) or CDMA2000. TDMA may be implemented asa radio technology such as global system for mobile communications(GSM)/general packet radio service (GPRS)/enhanced data rates for GSMevolution (EDGE). OFDMA may be implemented as a radio technology such asIEEE 802.11 (Wi-Fi), IEEE 802.16 (WiMAX), IEEE 802.20, evolved UTRA(E-UTRA), etc.

UTRA is a part of universal mobile telecommunications system (UMTS).3GPP LTE is a part of evolved UMTS (E-UMTS) using E-UTRA, adopting OFDMAfor DL and SC-FDMA for UL. LTE-advanced (LTE-A) is an evolution of 3GPPLTE.

While the various embodiments of the present disclosure are described inthe context of 3GPP LTE/LTE-A systems and 3GPP NR system in order toclarify the technical features of the various embodiments of the presentdisclosure, the various embodiments of the present disclosure is alsoapplicable to an IEEE 802.16e/m system, etc.

1. Overview of 3GPP System

1.1. Physical Channels and General Signal Transmission

In a wireless access system, a UE receives information from a basestation on a DL and transmits information to the base station on a UL.The information transmitted and received between the UE and the basestation includes general data information and various types of controlinformation. There are many physical channels according to thetypes/usages of information transmitted and received between the basestation and the UE.

FIG. 1 is a diagram illustrating physical channels and a signaltransmission method using the physical channels, which may be used invarious embodiments of the present disclosure.

When a UE is powered on or enters a new cell, the UE performs initialcell search (S11). The initial cell search involves acquisition ofsynchronization to a BS. Specifically, the UE synchronizes its timing tothe base station and acquires information such as a cell identifier (ID)by receiving a primary synchronization channel (P-SCH) and a secondarysynchronization channel (S-SCH) from the BS.

Then the UE may acquire information broadcast in the cell by receiving aphysical broadcast channel (PBCH) from the base station.

During the initial cell search, the UE may monitor a DL channel state byreceiving a downlink reference signal (DL RS).

After the initial cell search, the UE may acquire more detailed systeminformation by receiving a physical downlink control channel (PDCCH) andreceiving on a physical downlink shared channel (PDSCH) based oninformation of the PDCCH (S12).

Subsequently, to complete connection to the eNB, the UE may perform arandom access procedure with the eNB (S13 to S16). In the random accessprocedure, the UE may transmit a preamble on a physical random accesschannel (PRACH) (S13) and may receive a PDCCH and a random accessresponse (RAR) for the preamble on a PDSCH associated with the PDCCH(S14). The UE may transmit a PUSCH by using scheduling information inthe RAR (S15), and perform a contention resolution procedure includingreception of a PDCCH signal and a PDSCH signal corresponding to thePDCCH signal (S16).

When the random access procedure is performed in two steps, steps S13and S15 may be performed in one operation for a UE transmission, andsteps S14 and S16 may be performed in one operation for a BStransmission.

After the above procedure, the UE may receive a PDCCH and/or a PDSCHfrom the BS (S17) and transmit a physical uplink shared channel (PUSCH)and/or a physical uplink control channel (PUCCH) to the BS (S18), in ageneral UL/DL signal transmission procedure.

Control information that the UE transmits to the BS is genericallycalled uplink control information (UCI). The UCI includes a hybridautomatic repeat and request acknowledgement/negative acknowledgement(HARQ-ACK/NACK), a scheduling request (SR), a channel quality indicator(CQI), a precoding matrix index (PMI), a rank indicator (RI), etc.

In general, UCI is transmitted periodically on a PUCCH. However, ifcontrol information and traffic data should be transmittedsimultaneously, the control information and traffic data may betransmitted on a PUSCH. In addition, the UCI may be transmittedaperiodically on the PUSCH, upon receipt of a request/command from anetwork.

1.2. Radio Frame Structures

FIGS. 2A, 2B, and 3 illustrate radio frame structures in an LTE systemto which various embodiments of the present disclosure are applicable.

The LTE system supports frame structure type 1 for frequency divisionduplex (FDD), frame structure type 2 for time division duplex (TDD), andframe structure type 3 for an unlicensed cell (UCell). In the LTEsystem, up to 31 secondary cells (SCells) may be aggregated in additionto a primary cell (PCell). Unless otherwise specified, the followingoperation may be applied independently on a cell basis.

In multi-cell aggregation, different frame structures may be used fordifferent cells. Further, time resources (e.g., a subframe, a slot, anda subslot) within a frame structure may be generically referred to as atime unit (TU).

FIG. 2A illustrates frame structure type 1. Frame type 1 is applicableto both a full Frequency Division Duplex (FDD) system and a half FDDsystem.

A DL radio frame is defined by 10 1-ms subframes. A subframe includes 14or 12 symbols according to a cyclic prefix (CP). In a normal CP case, asubframe includes 14 symbols, and in an extended CP case, a subframeincludes 12 symbols.

Depending on multiple access schemes, a symbol may be an OFDM(A) symbolor an SC-FDM(A) symbol. For example, a symbol may refer to an OFDM(A)symbol on DL and an SC-FDM(A) symbol on UL. An OFDM(A) symbol may bereferred to as a cyclic prefix-OFDMA(A) (CP-OFDM(A)) symbol, and anSC-FMD(A) symbol may be referred to as a discrete Fouriertransform-spread-OFDM(A) (DFT-s-OFDM(A)) symbol.

One subframe may be defined by one or more slots according to asubcarrier spacing (SCS) as follows.

-   -   When SCS=7.5 kHz or 15 kHz, subframe #i is defined by two 0.5-ms        slots, slot #2i and slot #2i+1 (i=0˜9).    -   When SCS=1.25 kHz, subframe #i is defined by one 1-ms slot, slot        #2i.    -   When SCS=15 kHz, subframe #i may be defined by six subslots as        illustrated in Table 1.

Table 1 lists exemplary subslot configurations for one subframe (normalCP).

TABLE 1 Subslot number 0 1 2 3 4 5 Slot number 2i 2i + 1 Uplink subslotpattern 0, 1, 2 3, 4 5, 6 0, 1 2, 3 4, 5, 6 (Symbol number) Downlinksubslot 0, 1, 2 3, 4 5, 6 0, 1 2, 3 4, 5, 6 pattern 1 (Symbol number)Downlink subslot 0, 1 2, 3, 4 5, 6 0, 1 2, 3 4, 5, 6 pattern 2 (Symbolnumber)

FIG. 2B illustrates frame structure type 2. Frame structure type 2 isapplied to a TDD system. Frame structure type 2 includes two halfframes. A half frame includes 4 (or 5) general subframes and 1 (or 0)special subframe. According to a UL-DL configuration, a general subframeis used for UL or DL. A subframe includes two slots.

Table 2 lists exemplary subframe configurations for a radio frameaccording to UL-DL configurations.

TABLE 2 Uplink- Downlink- downlink to-Uplink config- Switch pointSubframe number uration periodicity 0 1 2 3 4 5 6 7 8 9 0 5 ms D S U U UD S U U U 1 5 ms D S U U D D S U U D 2 5 ms D S U D D D S U D D 3 10 ms D S U U U D D D D D 4 10 ms  D S U U D D D D D D 5 10 ms  D S U D D D DD D D 6 5 ms D S U U U D S U U D

In Table 2, D represents a DL subframe, U represents a UL subframe, andS represents a special subframe. A special subframe includes a downlinkpilot time slot (DwPTS), a guard period (GP), and an uplink pilot timeslot (UpPTS). The DwPTS is used for initial cell search,synchronization, or channel estimation at a UE. The UpPTS is used forchannel estimation at an eNB and acquisition of UL transmissionsynchronization at a UE. The GP is a period for cancelling interferenceof a UL caused by the multipath delay of a DL signal between a DL andthe UL.

Table 3 lists exemplary special subframe configurations.

TABLE 3 Normal cyclic prefix in downlink Extended cyclic prefix indownlink Special UpPTS UpPTS subframe Normal cyclic Extended cyclicNormal cyclic Extended cyclic configuration DwPTS prefix in uplinkprefix in uplink DwPTS prefix in uplink prefix in uplink 0  6592 · T_(s)(1 + X) · (1 + X) ·  7680 · T_(s) (1 + X) · (1+ X) · 1 19760 · T_(s)2192 · T_(s) 2560 · T_(s) 20480 · T_(s) 2192 · T_(s) 2560 · T_(s) 221952 · T_(s) 23040 · T_(s) 3 24144 · T_(s) 25600 · T_(s) 4 26336 ·T_(s)  7680 · T_(s) (2 + X) · (2 + X) · 5  6592 · T_(s) (2 + X) · (2 +X) · 20480 · T_(s) 2192 · T_(s) 2560 · T_(s) 6 19760 · T_(s) 2192 ·T_(s) 2560 · T_(s) 23040 · T_(s) 7 21952 · T_(s) 12800 · T_(s) 8 24144 ·T_(s) — — — 9 13168 · T_(s) — — — 10 13168 · T_(s) 13152 · T_(s) 12800 ·T_(s) — — —

In Table 3, X is configured by higher-layer signaling (e.g., radioresource control (RRC) signaling or the like) or given as 0.

FIG. 3 is a diagram illustrating frame structure type 3.

Frame structure type 3 may be applied to a UCell operation. Framestructure type 3 may be applied to, but not limited to, a licensedassisted access (LAA) SCell with a normal CP. A frame is 10 ms induration, including 10 1-ms subframes. Subframe #i is defined by twoconsecutive slots, slot #2i and slot #2i+1. Each subframe in a frame maybe used for a DL or UL transmission or may be empty. A DL transmissionoccupies one or more consecutive subframes, starting from any time in asubframe and ending at a boundary of a subframe or in a DwPTS of Table3. A UL transmission occupies one or more consecutive subframes.

FIG. 4 is a diagram illustrating a slot structure in an LTE system towhich various embodiments of the present disclosure are applicable.

Referring to FIG. 4 , a slot includes a plurality of orthogonalfrequency division multiplexing (OFDM) symbols in the time domain by aplurality of resource blocks (RBs) in the frequency domain. A symbol mayrefer to a symbol duration. A slot structure may be described by aresource grid including N^(DL/UL) _(RB)N^(RB) _(sc) subcarriers andN^(DL/UL) _(symb) symbols. N^(DL) _(RB) represents the number of RBs ina DL slot, and N^(UL) _(RB) represents the number of RBs in a UL slot.N^(DL) _(RB) and N^(UL) _(RB) are dependent on a DL bandwidth and a ULbandwidth, respectively. N^(DL) _(symb) represents the number of symbolsin the DL slot, and N^(UL) _(symb) represents the number of symbols inthe UL slot. N^(RB) _(sc) represents the number of subcarriers in oneRB. The number of symbols in a slot may vary according to an SCS and aCP length (see Table 1). For example, while one slot includes 7 symbolsin a normal CP case, one slot includes 6 symbols in an extended CP case.

An RB is defined as N^(DL/UL) _(symb) (e.g., 7) consecutive symbols inthe time domain by N^(RB) _(sc) (e.g., 12) consecutive subcarriers inthe frequency domain. The RB may be a physical resource block (PRB) or avirtual resource block (VRB), and PRBs may be mapped to VRBs in aone-to-one correspondence. Two RBs each being located in one of the twoslots of a subframe may be referred to as an RB pair. The two RBs of anRB pair may have the same RB number (or RB index). A resource with onesymbol by one subcarrier is referred to as a resource element (RE) ortone. Each RE in the resource grid may be uniquely identified by anindex pair (k, l) in a slot. k is a frequency-domain index ranging from0 to N^(DL/UL) _(RB)×N^(RB) _(sc)−1 and 1 is a time-domain index rangingfrom 0 to N^(DL/UL) _(symb)−1.

FIG. 5 is a diagram illustrating a UL subframe structure in an LTEsystem to which various embodiments of the present disclosure areapplicable.

Referring to FIG. 5 , one subframe 500 includes two 0.5-ms slots 501.Each slot includes a plurality of symbols 502, each corresponding to oneSC-FDMA symbol. An RB 503 is a resource allocation unit corresponding to12 subcarriers in the frequency domain by one slot in the time domain.

A UL subframe is divided largely into a control region 504 and a dataregion 505. The data region is communication resources used for each UEto transmit data such as voice, packets, and so on, including a physicaluplink shared channel (PUSCH). The control region is communicationresources used for each UE to transmit an ACK/NACK for a DL channelquality report or a DL signal, a UL scheduling request, and so on,including a physical uplink control channel (PUCCH).

A sounding reference signal (SRS) is transmitted in the last SC-FDMAsymbol of a subframe in the time domain.

FIG. 6 is a diagram illustrating a DL subframe structure in an LTEsystem to which various embodiments of the present disclosure areapplicable.

Referring to FIG. 6 , up to three (or four) OFDM(A) symbols at thebeginning of the first slot of a subframe corresponds to a controlregion. The remaining OFDM(A) symbols correspond to a data region inwhich a PDSCH is allocated, and a basic resource unit of the data regionis an RB. DL control channels include a physical control formatindicator channel (PCFICH), a physical downlink control channel (PDCCH),a physical hybrid-ARQ indicator channel (PHICH), and so on.

The PCFICH is transmitted in the first OFDM symbol of a subframe,conveying information about the number of OFDM symbols (i.e., the sizeof a control region) used for transmission of control channels in thesubframe. The PHICH is a response channel for a UL transmission,conveying a hybrid automatic repeat request (HARQ) acknowledgement(ACK)/negative acknowledgement (NACK) signal. Control informationdelivered on the PDCCH is called downlink control information (DCI). TheDCI includes UL resource allocation information, DL resource controlinformation, or a UL transmit (Tx) power control command for any UEgroup.

FIG. 7 is a diagram illustrating a radio frame structure in an NR systemto which various embodiments of the present disclosure are applicable.

The NR system may support multiple numerologies. A numerology may bedefined by a subcarrier spacing (SCS) and a cyclic prefix (CP) overhead.Multiple SCSs may be derived by scaling a default SCS by an integer N(or μ). Further, even though it is assumed that a very small SCS is notused in a very high carrier frequency, a numerology to be used may beselected independently of the frequency band of a cell. Further, the NRsystem may support various frame structures according to multiplenumerologies.

Now, a description will be given of OFDM numerologies and framestructures which may be considered for the NR system. Multiple OFDMnumerologies supported by the NR system may be defined as listed inTable 4. For a bandwidth part, μ and a CP are obtained from RRCparameters provided by the BS.

TABLE 4 μ Δf = 2^(μ) · 15[kHz] Cyclic prefix 0 15 Normal 1 30 Normal 260 Normal, Extended 3 120 Normal 4 240 Normal

In NR, multiple numerologies (e.g., SCSs) are supported to support avariety of 5G services. For example, a wide area in cellular bands issupported for an SCS of 15 kHz, a dense-urban area, a lower latency, anda wider carrier bandwidth are supported for an SCS of 30 kHz/60 kHz, anda larger bandwidth than 24.25 GHz is supported for an SCS of 60 kHz ormore, to overcome phase noise.

An NR frequency band is defined by two types of frequency ranges, FR1and FR2. FR1 may be a sub-6 GHz range, and FR2 may be an above-6 GHzrange, that is, a millimeter wave (mmWave) band.

Table 5 below defines the NR frequency band, by way of example.

TABLE 5 Frequency range Corresponding designation frequency rangeSubcarrier Spacing FR1  410 MHz-7125 MHz  15, 30, 60 kHz FR2 24250MHz-52600 MHz 60, 120, 240 kHz

Regarding a frame structure in the NR system, the time-domain sizes ofvarious fields are represented as multiples of a basic time unit for NR,T_(c)=1/(Δf_(max)*N_(f)) where Δf_(max)=480*10³ Hz and a value N_(f)related to a fast Fourier transform (FFT) size or an inverse fastFourier transform (IFFT) size is given as N_(f)=4096. T_(c) and T_(s)which is an LTE-based time unit and sampling time, given as T_(s)=1/((15kHz)*2048) are placed in the following relationship: T_(s)/T_(c)=64. DLand UL transmissions are organized into (radio) frames each having aduration of T_(f)=(Δf_(max)*N_(f)/100)*T_(c)=10 ms. Each radio frameincludes 10 subframes each having a duration ofT_(sf)=(Δf_(max)*N_(f)/1000)*T_(c)=1 ms. There may exist one set offrames for UL and one set of frames for DL. For a numerology μ, slotsare numbered with n^(μ) _(s)∈{0, . . . , N^(slot,μ) _(subframe)−1} in anincreasing order in a subframe, and with n^(μ) _(s,f)∈{0, . . . ,N^(slot,μ) _(frame)−1} in an increasing order in a radio frame. One slotincludes N^(μ) _(symb) consecutive OFDM symbols, and N^(μ) _(symb)depends on a CP. The start of a slot n^(μ) _(s) in a subframe is alignedin time with the start of an OFDM symbol n^(μ) _(s)*N^(μ) _(symb) in thesame subframe.

Table 6 lists the number of symbols per slot, the number of slots perframe, and the number of slots per subframe, for each SCS in a normal CPcase, and Table 7 lists the number of symbols per slot, the number ofslots per frame, and the number of slots per subframe, for each SCS inan extended CP case.

TABLE 6 μ N_(symb) ^(slot) N_(slot) ^(frame, μ) N_(slot) ^(subframe, μ)0 14 10 1 1 14 20 2 2 14 40 4 3 14 80 8 4 14 160 16

TABLE 7 μ N_(symb) ^(slot) N_(slot) ^(frame, μ) N_(slot) ^(subframe, μ)2 12 40 4

In the above tables, N^(slot) _(symb) represents the number of symbolsin a slot N^(frame,μ) _(slot) represents the number of slots in a frame,and N^(subframe,μ) _(slot) represents the number of slots in a subframe.

In the NR system to which various embodiments of the present disclosureare applicable, different OFDM(A) numerologies (e.g., SCSs, CP lengths,and so on) may be configured for a plurality of cells which areaggregated for one UE. Accordingly, the (absolute time) period of a timeresource including the same number of symbols (e.g., a subframe (SF), aslot, or a TTI) (generically referred to as a time unit (TU), forconvenience) may be configured differently for the aggregated cells.

FIG. 7 illustrates an example with μ=2 (i.e., an SCS of 60 kHz), inwhich referring to Table 6, one subframe may include four slots. Onesubframe={1, 2, 4} slots in FIG. 7 , which is exemplary, and the numberof slot(s) which may be included in one subframe is defined as listed inTable 6 or Table 7.

Further, a mini-slot may include 2, 4 or 7 symbols, fewer symbols than2, or more symbols than 7.

FIG. 8 is a diagram illustrating a slot structure in an NR system towhich various embodiments of the present disclosure are applicable.

Referring FIG. 8 , one slot includes a plurality of symbols in the timedomain. For example, one slot includes 7 symbols in a normal CP case and6 symbols in an extended CP case.

A carrier includes a plurality of subcarriers in the frequency domain.An RB is defined by a plurality of (e.g., 12) consecutive subcarriers inthe frequency domain.

A bandwidth part (BWP), which is defined by a plurality of consecutive(P)RBs in the frequency domain, may correspond to one numerology (e.g.,SCS, CP length, and so on).

A carrier may include up to N (e.g., 5) BWPs. Data communication may beconducted in an activated BWP, and only one BWP may be activated for oneUE. In a resource grid, each element is referred to as an RE, to whichone complex symbol may be mapped.

FIG. 9 is a diagram illustrating a self-contained slot structure towhich various embodiments of the present disclosure are applicable.

The self-contained slot structure may refer to a slot structure in whichall of a DL control channel, DL/UL data, and a UL control channel may beincluded in one slot.

In FIG. 9 , the hatched area (e.g., symbol index=0) indicates a DLcontrol region, and the black area (e.g., symbol index=13) indicates aUL control region. The remaining area (e.g., symbol index=1 to 12) maybe used for DL or UL data transmission.

Based on this structure, a BS and a UE may sequentially perform DLtransmission and UL transmission in one slot. That is, the BS and UE maytransmit and receive not only DL data but also a UL ACK/NACK for the DLdata in one slot. Consequently, this structure may reduce a timerequired until data retransmission when a data transmission erroroccurs, thereby minimizing the latency of a final data transmission.

In this self-contained slot structure, a predetermined length of timegap is required to allow the BS and the UE to switch from transmissionmode to reception mode and vice versa. To this end, in theself-contained slot structure, some OFDM symbols at the time ofswitching from DL to UL may be configured as a guard period (GP).

While the self-contained slot structure has been described above asincluding both of a DL control region and a UL control region, thecontrol regions may selectively be included in the self-contained slotstructure. In other words, the self-contained slot structure accordingto various embodiments of the present disclosure may cover a case ofincluding only the DL control region or the UL control region as well asa case of including both of the DL control region and the UL controlregion, as illustrated in FIG. 12 .

Further, the sequence of the regions included in one slot may varyaccording to embodiments. For example, one slot may include the DLcontrol region, the DL data region, the UL control region, and the ULdata region in this order, or the UL control region, the UL data region,the DL control region, and the DL data region in this order.

A PDCCH may be transmitted in the DL control region, and a PDSCH may betransmitted in the DL data region. A PUCCH may be transmitted in the ULcontrol region, and a PUSCH may be transmitted in the UL data region.

1.3. Channel Structures

1.3.1. DL Channel Structures

The BS transmits related signals to the UE on DL channels as describedbelow, and the UE receives the related signals from the BS on the DLchannels.

1.3.1.1. Physical Downlink Shared Channel (PDSCH)

The PDSCH conveys DL data (e.g., DL-shared channel transport block(DL-SCH TB)) and uses a modulation scheme such as quadrature phase shiftkeying (QPSK), 16-ary quadrature amplitude modulation (16QAM), 64QAM, or256QAM. A TB is encoded into a codeword. The PDSCH may deliver up to twocodewords. Scrambling and modulation mapping are performed on a codewordbasis, and modulation symbols generated from each codeword are mapped toone or more layers (layer mapping). Each layer together with ademodulation reference signal (DMRS) is mapped to resources, generatedas an OFDM symbol signal, and transmitted through a correspondingantenna port.

1.3.1.2. Physical Downlink Control Channel (PDCCH)

The PDCCH may deliver downlink control information (DCI), for example,DL data scheduling information, UL data scheduling information, and soon. The PUCCH may deliver uplink control information (UCI), for example,an acknowledgement/negative acknowledgement (ACK/NACK) information forDL data, channel state information (CSI), a scheduling request (SR), andso on.

The PDCCH carries downlink control information (DCI) and is modulated inquadrature phase shift keying (QPSK). One PDCCH includes 1, 2, 4, 8, or16 control channel elements (CCEs) according to an aggregation level(AL). One CCE includes 6 resource element groups (REGs). One REG isdefined by one OFDM symbol by one (P)RB.

FIG. 10 is a diagram illustrating the structure of one REG to whichvarious embodiments of the present disclosure are applicable.

In FIG. 10 , D represents an RE to which DCI is mapped, and R representsan RE to which a DMRS is mapped. The DMRS is mapped to REs #1, #5, and#9 along the frequency axis in one symbol

The PDCCH is transmitted in a control resource set (CORESET). A CORESETis defined as a set of REGs having a given numerology (e.g., SCS, CPlength, and so on). A plurality of CORESETs for one UE may overlap witheach other in the time/frequency domain. A CORESET may be configured bysystem information (e.g., a master information block (MIB)) or byUE-specific higher layer (RRC) signaling. Specifically, the number ofRBs and the number of symbols (up to 3 symbols) included in a CORESETmay be configured by higher-layer signaling.

For each CORESET, a precoder granularity in the frequency domain is setto one of the followings by higher-layer signaling:

-   -   sameAsREG-bundle: It equals to an REG bundle size in the        frequency domain.    -   allContiguousRBs: It equals to the number of contiguous RBs in        the frequency domain within the CORESET.

The REGs of the CORESET are numbered in a time-first mapping manner.That is, the REGs are sequentially numbered in an increasing order,starting with 0 for the first OFDM symbol of the lowest-numbered RB inthe CORESET.

CCE-to-REG mapping for the CORESET may be an interleaved type or anon-interleaved type.

FIGS. 11A and 11B are diagrams illustrating exemplary CCE-to-REG mappingtypes according to various embodiments of the present disclosure.

FIG. 11A is a diagram illustrating exemplary non-interleaved CCE-to-REGmapping according to various embodiments of the present disclosure.

-   -   Non-interleaved CCE-to-REG mapping (or localized CCE-to-REG        mapping): 6 REGs for a given CCE are grouped into one REG        bundle, and all of the REGs for the given CCE are contiguous.        One REG bundle corresponds to one CCE.

FIG. 11B is a diagram illustrating exemplary interleaved CCE-to-REGmapping.

-   -   Interleaved CCE-to-REG mapping (or distributed CCE-to-REG        mapping): 2, 3 or 6 REGs for a given CCE are grouped into one        REG bundle, and the REG bundle is interleaved in the CORESET. In        a CORESET including one or two OFDM symbols, an REG bundle        includes 2 or 6 REGs, and in a CORESET including three OFDM        symbols, an REG bundle includes 3 or 6 REGs. An REG bundle size        is configured on a CORESET basis.

FIG. 12 illustrates an exemplary block interleaver according to variousembodiments of the present disclosure.

For the above interleaving operation, the number A of rows in a (block)interleaver is set to one of 2, 3, and 6. If the number of interleavingunits for a given CORESET is P, the number of columns in the blockinterleaver is P/A. In the block interleaver, a write operation isperformed in a row-first direction, and a read operation is performed ina column-first direction, as illustrated in FIG. C4 . Cyclic shift (CS)of an interleaving unit is applied based on an ID which is configurableindependently of a configurable ID for the DMRS.

The UE acquires DCI delivered on a PDCCH by decoding (so-called blinddecoding) a set of PDCCH candidates. A set of PDCCH candidates decodedby a UE are defined as a PDCCH search space set. A search space set maybe a common search space (CSS) or a UE-specific search space (USS). TheUE may acquire DCI by monitoring PDCCH candidates in one or more searchspace sets configured by an MIB or higher-layer signaling. Each CORESETconfiguration is associated with one or more search space sets, and eachsearch space set is associated with one CORESET configuration. Onesearch space set is determined based on the following parameters.

-   -   controlResourceSetId: A set of control resources related to the        search space set.    -   monitoringSlotPeriodicityAndOffset: A PDCCH monitoring        periodicity (in slots) and a PDCCH monitoring offset (in slots).    -   monitoringSymbolsWithinSlot: A PDCCH monitoring pattern (e.g.,        the first symbol(s) in the CORESET) in a PDCCH monitoring slot.    -   nrofCandidates: The number of PDCCH candidates for each AL={1,        2, 4, 8, 16} (one of 0, 1, 2, 3, 4, 5, 6, and 8).

Table 8 lists exemplary features of the respective search space types.

TABLE 8 Search Type Space RNTI Use Case Type0-PDCCH Common SI-RNTI on aprimary SIB cell Decoding Type0A-PDCCH Common SI-RNTI on a primary SIBcell Decoding Type1-PDCCH Common RA-RNTI or TC-RNTI Msg2, Msg4 on aprimary cell decoding in RACH Type2-PDCCH Common P-RNTI on a primaryPaging cell Decoding Type3-PDCCH Common INT-RNTI, SFI-RNTI,TPC-PUSCH-RNTI, TPC- PUCCH-RNTI, TPC-SRS- RNTI, C-RNTI, MCS- C-RNTI, orCS-RNTI(s) UE C-RNTI, or MCS-C- User specific Specific RNTI, orCS-RNTI(s) PDSCH decoding

Table 9 lists exemplary DCI formats transmitted on the PDCCH.

TABLE 9 DCI format Usage 0_0 Scheduling of PUSCH in one cell 0_1Scheduling of PUSCH in one cell 1_0 Scheduling of PDSCH in one cell 1_1Scheduling of PDSCH in one cell 2_0 Notifying a group of UEs of the slotformat 2_1 Notifying a group of UEs of the PRB(s) and OFDM symbol(s)where UE may assume no transmission is intended for the UE 2_2Transmission of TPC commands for PUCCH and PUSCH 2_3 Transmission of agroup of TPC commands for SRS transmissions by one or more UEs

DCI format 0_0 may be used to schedule a TB-based (or TB-level) PUSCH,and DCI format 0_1 may be used to schedule a TB-based (or TB-level)PUSCH or a code block group (CBG)-based (or CBG-level) PUSCH. DCI format1_0 may be used to schedule a TB-based (or TB-level) PDSCH, and DCIformat 1_1 may be used to schedule a TB-based (or TB-level) PDSCH or aCBG-based (or CBG-level) PDSCH. DCI format 2_0 is used to deliverdynamic slot format information (e.g., a dynamic slot format indicator(SFI)) to the UE, and DCI format 2_1 is used to deliver DL preemptioninformation to the UE. DCI format 2_0 and/or DCI format 2_1 may bedelivered to the UEs of a group on a group common PDCCH (GC-PDCCH) whichis a PDCCH directed to a group of UEs.

1.3.2. UL Channel Structures

The UE transmits related signals on later-described UL channels to theBS, and the BS receives the related signals on the UL channels from theUE.

1.3.2.1. Physical Uplink Shared Channel (PUSCH)

The PUSCH delivers UL data (e.g., a UL-shared channel transport block(UL-SCH TB)) and/or UCI, in cyclic prefix-orthogonal frequency divisionmultiplexing (CP-OFDM) waveforms or discrete Fouriertransform-spread-orthogonal division multiplexing (DFT-s-OFDM)waveforms. If the PUSCH is transmitted in DFT-s-OFDM waveforms, the UEtransmits the PUSCH by applying transform precoding. For example, iftransform precoding is impossible (e.g., transform precoding isdisabled), the UE may transmit the PUSCH in CP-OFDM waveforms, and iftransform precoding is possible (e.g., transform precoding is enabled),the UE may transmit the PUSCH in CP-OFDM waveforms or DFT-s-OFDMwaveforms. The PUSCH transmission may be scheduled dynamically by a ULgrant in DCI or semi-statically by higher-layer signaling (e.g., RRCsignaling) (and/or layer 1 (L1) signaling (e.g., a PDCCH)) (a configuredgrant). The PUSCH transmission may be performed in a codebook-based ornon-codebook-based manner.

1.3.2.2. Physical Uplink Control Channel (PUCCH)

The PUCCH delivers UCI, an HARQ-ACK, and/or an SR and is classified as ashort PUCCH or a long PUCCH according to the transmission duration ofthe PUCCH. Table 10 lists exemplary PUCCH formats.

TABLE 10 Length in OFDM PUCCH symbols Number format N_(symb) ^(PUCCH) ofbits Usage Etc 0 1-2  ≤2 HARQ, SR Sequence selection 1 4-14 ≤2 HARQ,[SR] Sequence modulation 2 1-2  >2 HARQ, CSI, CP-OFDM [SR] 3 4-14 >2HARQ, CSI, DFT-s-OFDM [SR] (no UE multiplexing) 4 4-14 >2 HARQ, CSI,DFT-s-OFDM [SR] (Pre DFT OCC)

PUCCH format 0 conveys UCI of up to 2 bits and is mapped in asequence-based manner, for transmission. Specifically, the UE transmitsspecific UCI to the BS by transmitting one of a plurality of sequenceson a PUCCH of PUCCH format 0. Only when the UE transmits a positive SR,the UE transmits the PUCCH of PUCCH format 0 in a PUCCH resource for acorresponding SR configuration.

PUCCH format 1 conveys UCI of up to 2 bits and modulation symbols of theUCI are spread with an OCC (which is configured differently whetherfrequency hopping is performed) in the time domain. The DMRS istransmitted in a symbol in which a modulation symbol is not transmitted(i.e., transmitted in time division multiplexing (TDM)).

PUCCH format 2 conveys UCI of more than 2 bits and modulation symbols ofthe DCI are transmitted in frequency division multiplexing (FDM) withthe DMRS. The DMRS is located in symbols #1, #4, #7, and #10 of a givenRB with a density of ⅓. A pseudo noise (PN) sequence is used for a DMRSsequence. For 1-symbol PUCCH format 2, frequency hopping may beactivated.

PUCCH format 3 does not support UE multiplexing in the same PRBS, andconveys UCI of more than 2 bits. In other words, PUCCH resources ofPUCCH format 3 do not include an OCC. Modulation symbols are transmittedin TDM with the DMRS.

PUCCH format 4 supports multiplexing of up to 4 UEs in the same PRBS,and conveys UCI of more than 2 bits. In other words, PUCCH resources ofPUCCH format 3 includes an OCC. Modulation symbols are transmitted inTDM with the DMRS.

1.4. Bandwidth Part (BWP)

The NR system to which various embodiments of the present disclosure areapplicable may allocate/support up to 400-MHz frequency resources percomponent carrier (CC). If a UE operating in such a wideband CC alwayskeeps a radio frequency (RF) module on for the whole CC, the batteryconsumption of the UE may increase.

Alternatively, considering multiple use cases (e.g., eMBB, URLLC, mMTC,V2X, and so on) operating in one wideband CC, different numerologies(e.g., SCSs) may be supported for different frequency bands of the CC.

Alternatively, each UE may have a different capability for a maximumbandwidth.

In this regard, the BS may indicate to/configure the UE to operate onlyin a partial bandwidth, not the total bandwidth of the wideband CC. Thepartial bandwidth is referred to as a bandwidth part (BWP).

A BWP may include contiguous RBs in the frequency domain and correspondto one numerology (e.g., an SCS, a CP length, and/or a slot/mini-slotduration).

The BS may configure one or more BWPs in one CC configured for the UE.For example, the BS may configure a BWP occupying a relatively smallfrequency area in a PDCCH monitoring slot and schedule a PDSCH indicated(or scheduled) by a PDCCH in a larger BWP than the BWP. Alternatively,if UEs are concentrated in a specific BWP, the BS may configure anotherBWP for some of the UEs, for load balancing. Alternatively, forfrequency-domain inter-cell interference cancellation between adjacentcells, the BS may configure BWPs at both ends of the total bandwidthexcept for some spectrum in the same slot.

The BS may configure at least one DL/UL BWP for a UE associated with awideband CC, activate at least one of the configured DL/UL BWP(s) at aspecific time (by L1 signaling (e.g., DCI or the like), MAC signaling,or RRC signaling). The activated DL/UL BWP may be referred to as anactive DL/UL BWP. Before initial access or RRC connection setup, the UEmay not receive a DL/UL BWP configuration from the BS. A DL/UL BWP thatthe UE assumes in this situation is defined as an initial active DL/ULBWP.

More specifically, according to various embodiments of the presentdisclosure, the UE may perform the following BWP operation.

A UE, which has been configured to operate BWPs of a serving cell, isconfigured with up to four DL BWPs within the DL bandwidth of theserving cell by a higher-layer parameter (e.g., DL-BWP or BWP-Downlink)and up to four UL BWPs within the UL bandwidth of the serving cell by ahigher-layer parameter (e.g., UL BWP or BWP-Uplink).

When the UE fails to receive a higher-layer parameterinitialDownlinkBWP, an initial active DL BWP may be defined by thepositions and number of consecutive PRBs: consecutive PRBs from thelowest index to the highest index among PRBs included in a CORESET for aType-0 PDCCH CSS set. Further, the initial active DL BWP is defined byan SCS and a CP for PDCCH reception in the CORESET for the Type-0 PDCCHCSS set. Alternatively, the initial active DL BWP is provided by thehigher-layer parameter initialDownlinkBWP. For an operation in a primarycell or a secondary cell, an initial active UL BWP is indicated to theUE by a higher-layer parameter initialUplinkBWP. When a supplementary ULcarrier is configured for the UE, an initial active UL BWP on thesupplementary UL carrier may be indicated to the UE by initialUplinkBWin a higher-layer parameter supplementaryUplink.

When the UE has a dedicated BWP configuration, the UE may be providedwith a first active DL BWP for reception by a higher-layer parameterfirstActiveDownlinkBWP-Id and a first active UL BWP for transmission onthe carrier of the primary cell by a higher-layer parameterfirstActiveUplinkGBWP-Id.

For each DL BWP of a DL BWP set or each UL BWP of a UL BWP set, the UEmay be provided with the following parameters.

-   -   An SCS provided based on a higher-layer parameter (e.g.,        subcarrierSpacing).    -   A CP provided based on a higher-layer parameter (e.g.,        cyclicPrefix).    -   The number of common RBs and contiguous RBs is provided based on        a higher-layer parameter locationAndBandwidth. The higher-layer        parameter locationAndBandwidth indicates an offset RB_(start)        and a length L_(RB) based on a resource indication value (RIV).        It is assumed that N^(size) _(BWP) is 275 and O_(carrier) is        provided by offsetToCarrier for the higher-layer parameter        subcarrierSpacing.    -   An index in the set of DL BWPs or the set of UL BWPs, provided        based on a higher-layer parameter (e.g., bwp-Id) in UL and DL        independently.    -   A BWP-common set parameter or BWP-dedicated set parameter        provided based on a higher-layer parameter (e.g., bwp-Common or        bwp-Dedicated).

For an unpaired spectrum operation, a DL BWP in a set of DL BWPs withindexes provided by a higher-layer parameter (e.g., bwp-Id) is linked toa UL BWP in a set of UL BWPs with the same indexes, when the DL BWPindex and the UL BWP index are identical. For the unpaired spectrumoperation, when the higher-layer parameter bwp-Id of a DL BWP is thesame as the higher-layer parameter bwp-Id of a UL BWP, the UE does notexpect to receive a configuration in which the center frequency for theDL BWP is different from the center frequency for the UL BWP.

For each DL BWP in a set of DL BWPs of the primary cell (referred to asPCell) or of a PUCCH secondary cell (referred to as PUCCH-SCell), the UEmay configure CORESETs for every CSS set and a USS. The UE does notexpect to be configured without a CSS on the PCell or the PUCCH-SCell inan active DL BWP.

When the UE is provided with controlResourceSetZero and searchSpaceZeroin a higher-layer parameter PDCCH-ConfigSIB1 or a higher-layer parameterPDCCH-ConfigCommon, the UE determines a CORESET for a search space setbased on controlResourcesetZero and determines corresponding PDCCHmonitoring occasions. When the active DL BWP is not the initial DL BWP,the UE determines PDCCH monitoring occasions for the search space set,only if the bandwidth of the CORESET is within the active DL BWP and theactive DL BWP has the same SCS configuration and CP as the initial DLBWP.

For each UL BWP in a set of UL BWPs of the PCell or the PUCCH-SCell, theUE is configured with resource sets for PUCCH transmissions.

The UE receives a PDCCH and a PDSCH in a DL BWP according to aconfigured SCS and CP length for the DL BWP. The UE transmits a PUCCHand a PUSCH in a UL BWP according to a configured SCS and CP length forthe UL BWP.

When a bandwidth part indicator field is configured in DCI format 1_1,the value of the bandwidth part indicator field indicates an active DLBWP in the configured DL BWP set, for DL receptions. When a bandwidthpart indicator field is configured in DCI format 0_1, the value of thebandwidth part indicator field indicates an active UL BWP in theconfigured UL BWP set, for UL transmissions.

If a bandwidth part indicator field is configured in DCI format 0_1 orDCI format 1_1 and indicates a UL or DL BWP different from the active ULBWP or DL BWP, respectively, the UE may operate as follows.

-   -   For each information field in the received DCI format 0_1 or DCI        format 1_1,        -   if the size of the information field is smaller than a size            required for interpretation of DCI format 0_1 or DCI format            1_1 for the UL BWP or DL BWP indicated by the bandwidth part            indicator, the UE prepends zeros to the information field            until its size is the size required for the interpretation            of the information field for the UL BWP or DL BWP before the            information field of DCI format 0_1 or DCI format 1_1 is            interpreted.        -   if the size of the information field is larger than the size            required for interpretation of DCI format 0_1 or DCI format            1_1 for the UL BWP or DL BWP indicated by the bandwidth part            indicator, the UE uses as many least significant bits (LSBs)            of DCI format 0_1 or DCI format 1_1 as the size required for            the UL BWP or DL BWP indicated by the bandwidth part            indicator before interpreting the information field of DCI            format 0_1 or DCI format 1_1.    -   The UE sets the active UL BWP or DL BWP to the UL BWP or DL BWP        indicated by the bandwidth part indicator in DCI format 0_1 or        DCI format 1_1.

The UE does not expect to detect format 1_1 or DCI format 0_1 indicatingan active DL BWP or active UL BWP change with a time-domain resourceassignment field providing a slot offset value smaller than a delayrequired for the UE for an active DL BWP change or UL BWP change.

When the UE detects DCI format 1_1 indicating an active DL BWP changefor a cell, the UE is not required to receive or transmit a signal inthe cell during a time period from the end of the third symbol of a slotin which the UE receives a PDCCH including DCI format 1_1 until thebeginning of a slot indicated by the slot offset value of thetime-domain resource assignment field in DCI format 1_1.

If the UE detects DCI format 0_1 indicating an active UL BWP change fora cell, the UE is not required to receive or transmit a signal in thecell during a time period from the end of the third symbol of a slot inwhich the UE receives a PDCCH including DCI format 0_1 until thebeginning of a slot indicated by the slot offset value of thetime-domain resource assignment field in DCI format 0_1.

The UE does not expect to detect DCI format 1_1 indicating an active DLBWP change or DCI format 0_1 indicating an active UL BWP change in aslot other than the first slot of a set of slots for the SCS of a cellthat overlaps with a time period during which the UE is not required toreceive or transmit a signal for an active BWP change in a differentcell.

The UE expects to detect DCI format 0_1 indicating an active UL BWPchange or DCI format 1_1 indicating an active DL BWP change, only if acorresponding PDCCH is received within the first 3 symbols of a slot.

For the serving cell, the UE may be provided with a higher-layerparameter defaultDownlinkBWP-Id indicating a default DL BWP among theconfigured DL BWPs. If the UE is not provided with a default DL BWP bydefaultDownlinkBWP-Id, the default DL BWP may be set to the initialactive DL BWP.

When the UE is provided with a timer value for the PCell by ahigher-layer parameter bwp-InactivityTimer and the timer is running, theUE decrements the timer at the end of a subframe for FR1 (below 6 GHz)or at the end of a half subframe for FR2 (above 6 GHz), if a restartingcondition is not met during a time period corresponding to the subframefor FR1 or a time period corresponding to the half-subframe for FR2.

For a cell in which the UE changes an active DL BWP due to expiration ofa BWP inactivity timer and for accommodating a delay in the active DLBWP change or the active UL BWP change required by the UE, the UE is notrequired to receive or transmit a signal in the cell during a timeperiod from the beginning of a subframe for FR1 or a half subframe forFR2, immediately after the BWP inactivity timer expires until thebeginning of a slot in which the UE may receive or transmit a signal.

When the BWP inactivity timer of the UE for the specific cell expireswithin the time period during which the UE is not required to receive ortransmit a signal for the active UL/DL BWP change in the cell or in adifferent cell, the UE may delay the active UL/DL BWP change triggeredby expiration of the BWP activity timer until the subframe for FR1 orthe half-subframe for FR2 immediately after the UE completes the activeUL/DL BWP change in the cell or in the different cell.

When the UE is provided with a first active DL BWP by a higher-layerparameter firstActiveDownlinkBWP-Id and a first active UL BWP by ahigher-layer parameter firstActiveUplinkBWP-Id on a carrier of thesecondary cell, the UE uses the indicated DL BWP and the indicated ULBWP as the respective first active DL BWP and first active UL BWP on thecarrier of the secondary cell.

For a paired spectrum operation, when the UE changes an active UL BWP onthe PCell during a time period between a detection time of DCI format 1_0 or DCI format 1_1 and a transmission time of a corresponding PUCCHincluding HARQ-ACK information, the UE does not expect to transmit thePUCCH including the HARQ-ACK information in PUCCH resources indicated byDCI format 1_0 or DCI format 1_1.

When the UE performs radio resource management (RRM) measurement for abandwidth outside the active DL BWP for the UE, the UE does not expectto monitor a PDCCH.

1.5. Slot Configuration

In various embodiments of the present disclosure, a slot format includesone or more DL symbols, one or more UL symbols, and a flexible symbol.In various embodiments of the present disclosure, the correspondingconfigurations will be described as DL, UL, and flexible symbol(s),respectively, for the convenience of description.

The following may be applied to each serving cell.

When the UE is provided with a higher-layer parameterTDD-UL-DL-ConfigurationCommon, the UE may configure a slot format perslot over a certain number of slots, indicated by the higher-layerparameter TDD-UL-DL-ConfigurationCommon.

The higher-layer parameter TDD-UL-DL-ConfigurationCommon may provide thefollowing.

-   -   A reference SCS configuration μ_(ref) based on a higher-layer        parameter referenceSubcarrierSpacing.    -   A higher-layer parameter pattern1.

The higher-layer parameter pattern1 may provide the following.

-   -   A slot configuration periodicity P msec based on a higher-layer        parameter dl-UL-TransmissionPeriodicity.    -   The number d_(slots) of slots including only DL symbols based on        a higher-layer parameter nrofDownlinkSlots.    -   The number d_(sym) of DL symbols based on a higher-layer        parameter nrofDownlinkSymbols.    -   The number u_(slots) of slots including only UL symbols based on        a higher-layer parameter nrofUplinkSlots.    -   The number U_(sym) of UL symbols based on a higher-layer        parameter nrofUplinkSymbols.

For an SCS configuration μ_(ref)=3, only P=0.625 msec may be valid. Foran SCS configuration μ_(ref)=2 or μ_(ref)=3, only P=1.25 msec may bevalid. For an SCS configuration μ_(ref)=1, μ_(ref)=2 or μ_(ref)=3, onlyP=2.5 msec may be valid.

The slot configuration periodicity (P msec) includes S slots given byS=P·2^(μ) ^(ref) in an SCS configuration μ_(ref). The first d_(slots)slots of the S slots include only DL symbols, and the last u_(slots)slots of the S slots include only UL symbols. d_(sym) symbols followingthe first d_(slots) slots are DL symbols. u_(sym) symbols preceding theu_(slots) slots are UL symbols. The remaining(S−d_(slots)−u_(slots))·N_(symb) ^(slot)−d_(sym)−u_(sym) symbols areflexible symbols.

The first symbol of every 20/P period is the first symbol of aneven-numbered frame.

When the higher-layer parameter TDD-UL-DL-ConfigurationCommon provideshigher-layer parameters pattern1 and pattern2, the UE configures a slotformat per slot over a first number of slots based on the higher-layerparameter pattern1, and a slot format per slot over a second number ofslots based on the higher-layer parameter pattern2.

The higher-layer parameter pattern2 may provide the following.

-   -   A slot configuration periodicity P₂ msec based on a higher-layer        parameter dl-UL-TransmissionPeriodicity.    -   The number d_(slots,2) of slots including only DL symbols based        on a higher-layer parameter nrofDownlinkSlots.    -   The number d_(sym,2) of DL symbols based on a higher-layer        parameter nrofDownlinkSymbols.    -   The number u_(slots,2) of slots including only UL symbols based        on a higher-layer parameter nrofUplinkSlots.    -   The number u_(sym,2) of UL symbols based on a higher-layer        parameter nrofUplinkSymbols.

A P₂ value applicable according to an SCS configuration is equal to a Pvalue applicable according to the SCS configuration.

A slot configuration periodicity P+P2 msec includes the first S slotswhere S=P·2^(μ) ^(ref) and the second S₂ slots where S₂=P₂·2^(μ) ^(ref).

The first d_(slots,2) ones of the S₂ slots include only DL symbols, andthe last u_(slots,2) ones of the S₂ slots include only UL symbols.d_(sym,2) symbols following the first d_(slots,2) slots are DL symbols.u_(sym,2) symbols preceding the u_(slots,2) slots are UL symbols. Theremaining (S₂−d_(slots,2)−u_(slots,2))·N_(symb)^(slot)−d_(sym,2)−u_(sym,2) symbols are flexible symbols.

The UE expects the value of P+P₂ to be divided by 20 msec without aremainder. In other words, the UE expects the value of P+P2 to be aninteger multiple of 20 msec.

The first symbol of every 20/(P+P₂) period is the first symbol of aneven-numbered frame.

The UE expects that the reference SCS configuration μ_(ref) is smallerthan or equal to an SCS configuration μ for any configured DL BWP or ULBWP. Each slot (configuration) provided by the higher-layer parameterpattern1 or pattern2 is applicable to 2^((μ-μ) ^(ref) ⁾ consecutiveslots in the active DL BWP or active UL BWP in the first slot whichstarts at the same time as the first slot for the reference SCSconfiguration μ_(ref). Each DL, flexible, or UL symbol for the referenceSCS configuration μ_(ref) corresponds to 2^((μ-μ) ^(ref) ⁾ consecutiveDL, flexible, or UL symbols for the SCS configuration μ.

When the UE is additionally provided with a higher-layer parameterTdd-UL-DL-ConfigurationDedicated, the higher-layer parameterTdd-UL-DL-ConfigurationDedicated overrides only flexible symbols perslot over the number of slots as provided by the higher-layer parameterTdd-UL-DL-ConfigurationCommon.

The higher-layer parameter Tdd-UL-DL-ConfigurationDedicated may providethe following.

-   -   A set of slot configurations based on a higher-layer parameter        slotSpecificConfigurationsToAddModList.    -   Each slot configuration in the set of slot configurations.    -   A slot index based on a higher-layer parameter slotIndex.    -   A set of symbols based on a higher-layer parameter symbols.        -   If the higher-layer parameter symbols=allDownlink, all            symbols in the slot are DL symbols.        -   If the higher-layer parameter symbols=allUplink, all symbols            in the slot are UL symbols.        -   If the higher-layer parameter symbols=explicit, the            higher-layer parameter nrofDownlinkSymbols provides the            number of first DL symbols in the slot, and the higher-layer            parameter nrofUplinkSymbols provides the number of last UL            symbols in the slot. If the higher-layer parameter            nrofDownlinkSymbols is not provided, this implies that there            are no first DL symbols in the slot. If the higher-layer            parameter nrofUplinkSymbols is not provided, this implies            that there are no last UL symbols in the slot. The remaining            symbols in the slot are flexible symbols.

For each slot having an index provided by a higher-layer parameterslotIndex, the UE applies a (slot) format provided by a correspondingsymbols. The UE does not expect the higher-layer parameterTDD-UL-DL-ConfigurationDedicated to indicate, as UL or DL, a symbol thatthe higher-layer parameter TDD-UL-DL-ConfigurationCommon indicates as DLor UL.

For each slot configuration provided by the higher-layer parameterTDD-UL-DL-ConfigurationDedicated, a reference SCS configuration is thereference SCS configuration μ_(ref) provided by the higher-layerparameter TDD-UL-DL-ConfigurationCommon.

A slot configuration periodicity and the number of DL/UL/flexiblesymbols in each slot of the slot configuration periodicity is determinedbased on the higher-layer parameters TDD-UL-DL-ConfigurationCommon andTDD-UL-DL-ConfigurationDedicated, and the information is common to eachconfigured BWP.

The UE considers symbols in a slot indicated as DL by the higher-layerparameter TDD-UL-DL-ConfigurationCommon orTDD-UL-DL-ConfigurationDedicated to be available for signal reception.Further, the UE considers symbols in a slot indicated as UL by thehigher-layer parameter TDD-UL-DL-ConfigurationCommon orTDD-UL-DL-ConfigurationDedicated to be available for signaltransmission.

If the UE is not configured to monitor a PDCCH for DCI format 2_0, for aset of symbols of a slot that are indicated as flexible by thehigher-layer parameter TDD-UL-DL-ConfigurationCommon orTDD-UL-DL-ConfigurationDedicated, or when the higher-layer parametersTDD-UL-DL-ConfigurationCommon and TDD-UL-DL-ConfigurationDedicated arenot provided to the UE, the UE may operate as follows.

-   -   The UE may receive a PDSCH or a CSI-RS in the set of symbols of        the slot, when the UE receives a corresponding indication by DCI        format 1_0, DCI format 1_1, or DCI format 0_1.    -   The UE may transmit a PUSCH, a PUCCH, a PRACH, or an SRS in the        set of symbols of the slot, if the UE receives a corresponding        indication by DCI format 0_0, DCI format 0_1, DCI format 1_0,        DCI format 1_1, or DCI format 2_3.

It is assumed that the UE is configured by the higher layer to receive aPDCCH, a PDSCH, or a CSI-RS in a set of symbols of a slot. When the UEdoes not detect DCI format 0_0, DCI format 0_1, DCI format 1_0, DCIformat 1_1, or DCI format 2_3 that indicates to the UE to transmit aPUSCH, a PUCCH, a PRACH, or an SRS in at least one symbol of the set ofsymbols of the slot, the UE may receive the PDCCH, the PDSCH, or theCSI-RS. Otherwise, that is, when the UE detects DCI format 0_0, DCIformat 0_1, DCI format 1_0, DCI format 1_1, or DCI format 2_3 thatindicates to the UE to transmit a PUSCH, a PUCCH, a PRACH, or an SRS inat least one symbol of the set of symbols of the slot, the UE does notreceive the PDCCH, the PDSCH, or the CSI-RS in the set of symbols of theslot.

When the UE is configured by the higher layer to transmit an SRS, aPUCCH, a PUSCH, or a PRACH in a set of symbols of a slot and detects DCIformat 1_0, DCI format 1_1, or DCI format 0_1 indicating to the toreceive a CSI-RS or a PDSCH in a subset of symbols from the set ofsymbols, the UE operates as follows.

-   -   The UE does not expect to cancel signal transmission in a subset        of symbols that occur after fewer symbols than a PUSCH        preparation time T_(proc,2) for a corresponding UE processing        capability on the assumption that d_(2,1)=1, relative to the        last symbol of a CORESET in which the UE detects DCI format 1_0,        DCI format 1_1, or DCI format 0_1.    -   The UE cancels the PUCCH, PUSCH, or PRACH transmission in the        remaining symbols of the set of symbols, and cancels the SRS        transmission in the remaining symbols of the set of symbols.

For a set of symbols of a slot that are indicated as UL by thehigher-layer parameter TDD-UL-DL-ConfigurationCommon orTDD-UL-DL-ConfigurationDedicated, the UE does not receive a PDCCH, aPDSCH, or a CSI-RS in the set of symbols of the slot.

For a set of symbols of a slot that are indicated as DL by thehigher-layer parameter TDD-UL-DL-ConfigurationCommon orTDD-UL-DL-ConfigurationDedicated, the UE does not transmit a PUSCH, aPUCCH, a PRACH, or an SRS in the set of symbols of the slot.

For a set of symbols of a slot that are indicated as flexible by thehigher-layer parameter TDD-UL-DL-ConfigurationCommon orTDD-UL-DL-ConfigurationDedicated, the UE does not expect to receive adedicated configuration for transmission from the UE and a dedicatedconfiguration for reception at the UE in the set of symbols of the slot.

For a set of symbols of a slot indicated by a higher-layer parameterssb-PositionsInBurst in a higher-layer parameterSystemInformationBlockType1 or ServingCellConfigCommon, for reception ofSS/PBCH blocks, the UE does not transmit a PUSCH, a PUCCH, or a PRACH inthe slot if a transmission overlaps with any symbol of the set ofsymbols, and the UE does not transmit an SRS in the set of symbols ofthe slot. When the higher-layer parameter TDD-UL-DL-ConfigurationCommonor TDD-UL-DL-ConfigDedicated is provided to the UE, the UE does notexpect the set of symbols of the slot to be indicated as UL by thehigher-layer parameter.

For a set of symbols of a slot corresponding to a valid PRACH occasion,and N_(gap) symbols before the valid PRACH occasion, when a signalreception overlaps with any symbol of the set of symbols in the slot,the UE does not receive a PDCCH, a PDSCH, or a CSI-RS for a Type1-PDCCHCSS set. The UE does not expect the set of symbols of the slot to beindicated as DL by the higher-layer parameterTDD-UL-DL-ConfigurationCommon or TDD-UL-DL-ConfigDedicated.

For a set of symbols of a slot indicated by a higher-layer parameterpdcch-ConfigSIB1 in an MIB for a CORESET for a Type0-PDCCH CSS set, theUE does not expect the set of symbols to be indicated as UL by thehigher-layer parameter TDD-UL-DL-ConfigurationCommon orTDD-UL-DL-ConfigDedicated.

When the UE is scheduled by DCI format 1_1 to receive a PDSCH overmultiple slots, and the higher-layer parameterTDD-UL-DL-ConfigurationCommon or TDD-UL-DL-ConfigDedicated indicatesthat, for one of the multiple slots, at least one symbol in a set ofsymbols in which the UE is scheduled to receive a PDSCH in the slot is aUL symbol, the UE does not receive the PDSCH in the slot.

When the UE is scheduled by DCI format 0_1 to transmit a PUSCH overmultiple slots, and the higher-layer parameterTDD-UL-DL-ConfigurationCommon or TDD-UL-DL-ConfigDedicated indicatesthat, for one of the multiple slots, at least one symbol in a set ofsymbols in which the UE is scheduled to receive a PDSCH in the slot is aDL symbol, the UE does not transmit the PUSCH in the slot.

A detailed description will be given below of a UE operation fordetermining a slot format. The UE operation may apply for a serving cellincluded in a set of serving cells configured for a UE by higher-layerparameters slotFormatCombToAddModList and slotFormatCombToReleaseList.

If the UE is configured with a higher-layer parameterSlotFormatIndicator, the UE is provided with an SFI-RNTI by ahigher-layer parameter sfi-RNTI and with a payload size of DCI format2_0 by a higher-layer parameter dci-PayloadSize.

For one or more serving cells, the UE is also provided with aconfiguration for a search space set S and a corresponding CORESET P.The search space set S and the corresponding CORESET P may be providedfor monitoring M_(p,s) ^((L) ^(SFI) ⁾ PDCCH candidates for DCI format2_0 with a CCE aggregation level including L_(SFI) CCEs.

The M_(p,s) ^((L) ^(SFI) ⁾ PDCCH candidates are the first M_(p,s) ^((L)^(SFI) ⁾ PDCCH candidates for the CCE aggregation level L_(SFI) for thesearch space set S in the CORESET P.

For each serving cell in the set of serving cells, the UE may beprovided with:

-   -   an ID of the serving cell based on a higher-layer parameter        servingCellId.    -   a location of an SFI-index field in DCI format 2_0 based on a        higher-layer parameter positionInDCI.    -   a set of slot format combinations based on a higher-layer        parameter slotFormatCombinations, where each slot format        combination in the set of slot format combinations includes        -   one or more slot formats based on a higher-layer parameter            slotFormats for the slot format combination, and        -   mapping for the slot format combination provided by the            higher-layer parameter slotFormats to a corresponding            SFI-index field value in DCI format 2_0 provided by a            higher-layer parameter slotFormatCombinationId.    -   for an unpaired spectrum operation, a reference SCS        configuration μ_(SFI) based on a higher-layer parameter        subcarrierSpacing. When a supplementary UL carrier is configured        for the serving cell, a reference SCS configuration μ_(SFI, SUL)        based on a higher-layer parameter subcarrierSpacing2 for the        supplementary UL carrier.    -   for a paired spectrum operation, a reference SCS configuration        μ_(SFI, DL) for a DL BWP based on the higher-layer parameter        subcarrierSpacing and a reference SCS configuration μ_(SFI, UL)        for an UL BWP based on the higher-layer parameter        subcarrierSpacing2.

An SFI-index field value in DCI format 2_0 indicates to the UE a slotformat for each slot in a number of slots for each DL BWP or each UL BWPstarting from a slot in which the UE detects DCI format 2_0. The numberof slots is equal to or larger than a PDCCH monitoring periodicity forDCI format 2_0. The SFI-index field includes max {┌log₂(maxSFIindex+1)┐,1} bits where maxSFIindex is the maximum of the values provided by thecorresponding higher-layer parameter slotFormatCombinationId. A slotformat is identified by a corresponding format index as provided inTable 11 to Table 14. In Table 11 to Table 14, ‘D’ denotes a DL symbol,‘U’ denotes a UL symbol, and ‘F’ denotes a flexible symbol. In Table 11to Table 14, ‘D’ denotes a DL symbol, ‘U’ denotes a UL symbol, and ‘F’denotes a flexible symbol.

TABLE 11 For- Symbol number in a slot mat 0 1 2 3 4 5 6 7 8 9 10 11 1213 0 D D D D D D D D D D D D D D 1 U U U U U U U U U U U U U U 2 F F F FF F F F F F F F F F 3 D D D D D D D D D D D D D F 4 D D D D D D D D D DD D F F 5 D D D D D D D D D D D F F F 6 D D D D D D D D D D F F F F 7 DD D D D D D D D F F F F F 8 F F F F F F F F F F F F F U 9 F F F F F F FF F F F F U U 10 F U U U U U U U U U U U U U 11 F F U U U U U U U U U UU U 12 F F F U U U U U U U U U U U 13 F F F F U U U U U U U U U U 14 F FF F F U U U U U U U U U

TABLE 12 15 F F F F F F U U U U U U U U 16 D F F F F F F F F F F F F F17 D D F F F F F F F F F F F F 18 D D D F F F F F F F F F F F 19 D F F FF F F F F F F F F U 20 D D F F F F F F F F F F F U 21 D D D F F F F F FF F F F U 22 D F F F F F F F F F F F U U 23 D D F F F F F F F F F F U U24 D D D F F F F F F F F F U U 25 D F F F F F F F F F F U U U 26 D D F FF F F F F F F U U U 27 D D D F F F F F F F F U U U 28 D D D D D D D D DD D D F U 29 D D D D D D D D D D D F F U 30 D D D D D D D D D D F F F U31 D D D D D D D D D D D F U U 32 D D D D D D D D D D F F U U

TABLE 13 33 D D D D D D D D D F F F U U 34 D F U U U U U U U U U U U U35 D D F U U U U U U U U U U U 36 D D D F U U U U U U U U U U 37 D F F UU U U U U U U U U U 38 D D F F U U U U U U U U U U 39 D D D F F U U U UU U U U U 40 D F F F U U U U U U U U U U 41 D D F F F U U U U U U U U U42 D D D F F F U U U U U U U U 43 D D D D D D D D D F F F F U 44 D D D DD D F F F F F F U U 45 D D D D D D F F U U U U U U

TABLE 14 46 D D D D D F U D D D D D F U 47 D D F U U U U D D F U U U U48 D F U U U U U D F U U U U U 49 D D D D F F U D D D D F F U 50 D D F FU U U D D F F U U U 51 D F F U U U U D F F U U U U 52 D F F F F F U D FF F F F U 53 D D F F F F U D D F F F F U 54 F F F F F F F D D D D D D D55 D D F F F U U U D D D D D D 56-254 Reserved 255  UE determines theslot format for the slot based on TDD-UL-DL- ConfigurationCommon, orTDD-UL-DL-ConfigDedicated and, if any, on detected DCI formats

If a PDCCH monitoring periodicity for DCI format 2_0, provided to the UEfor the search space set S by a higher-layer parametermonitoringSlotPeriodicityAndOffset, is smaller than the duration of aslot format combination that the UE obtains in a PDCCH monitoringoccasion for DCI format 2_0 by a corresponding SFI-index field value,and the UE detects more than one DCI format 2_0 indicating a slot formatfor a slot, the UE expects each of the more than one DCI format 2_0 toindicate the same (slot) format for the slot.

The UE does not expect to be configured to monitor a PDCCH for DCIformat 2_0 on a second serving cell that uses a larger SCS than theserving cell.

For an unpaired spectrum operation of the UE on a serving cell, the UEis provided, by a higher-layer parameter subcarrierSpacing, with areference SCS configuration μ_(SFI) for each slot format in acombination of slot formats indicated by an SFI-index field value in DCIformat 2_0. The UE expects that for a reference SCS configurationμ_(SFI) and for an SCS configuration μ for an active DL BWP or an activeUL BWP, μ≥μ_(SFI). Each slot format in the combination of slot formatsindicated by the SFI-index field value in DCI format 2_0 is applicableto

2^((μ − μ_(SFI)))consecutive slots in the active DL BWP or the active UL BWP in which thefirst slot starts at the same time as the first slot for the referenceSCS configuration μ_(SFI). Each DL or flexible or UL symbol for thereference SCS configuration μ_(SFI) corresponds to

2^((μ − μ_(SFI)))consecutive DL or flexible or UL symbols for the SCS configuration μ.

For a paired spectrum operation of the UE on a serving cell, theSFI-index field in DCI format 2_0 includes a combination of slot formatsfor a reference DL BWP and a combination of slot formats for a referenceUL BWP of the serving cell. The UE is provided with a reference SCSconfiguration μ_(SFI) for each slot format in the combination of slotformats indicated by the value. For the reference SCS configurationμ_(SFI) and an SCS configuration μ for the active DL BWP or the activeUL BWP, the UE expects that μ≥μ_(SFI). The UE is provided, by ahigher-layer parameter subcarrierSpacing, with a reference SCSconfiguration μ_(SFI, DL) for the combination of slot formats indicatedby the SFI-index field value in DCI format 2_0 for the reference DL BWPof the serving cell. The UE is provided, by a higher-layer parametersubcarrierSpacing2, with a reference SCS configuration μ_(SFI, UL) forthe combination of slot formats indicated by the SFI-index field valuein DCI format 2_0 for the reference UL BWP of the serving cell. If

μ_(SFI, DL) ≥ μ_(SFI, UL),for each

2^((μ_(SFI, DL) − μ_(SFI, UL))) + 1value provided by a value of the higher-layer parameter slotFormats, thevalue of the higher-layer parameter slotFormats is determined based on avalue of the higher-layer parameter slotFormatCombinationId in thehigher-layer parameter slotFormatCombination, the value of thehigher-layer parameter slotFormatCombinationId is set based on the valueof the SFI-index field value in DCI format 2_0, the first 2^((μ)^(SFI, DL) ^(−μ) ^(SFI, UL) ⁾ values for the combination of slot formatsare applicable to the reference DL BWP, and the next value is applicableto the reference UL BWP. If

μ_(SFI, DL) < μ_(SFI, UL),for each

2^((μ_(SFI, UL) − μ_(SFI, DL))) + 1value provided by the higher-layer parameter slotFormats, the firstvalue for the combination of slot formats is applicable to the referenceDL BWP and the next

2^((μ_(SFI, UL) − μ_(SFI, DL)))values are applicable to the reference UL BWP.

For a set of symbols of a slot, the UE does not expect to detect DCIformat 2_0 with an SFI-index field value indicating the set of symbolsin the slot as UL and to detect DCI format 1_0, DCI format 1_1, or DCIformat 0_1 indicating to the UE to receive a PDSCH or a CSI-RS in theset of symbols of the slot.

For a set of symbols of a slot, the UE does not expect to detect DCIformat 2_0 with an SFI-index field value indicating the set of symbolsin the slot as DL and to detect DCI format 0_0, DCI format 0_1, DCIformat 1_0, DCI format 1_1, DCI format 2_3, or an RAR UL grantindicating to the UE to transmit a PUSCH, a PUCCH, a PRACH, or an SRS inthe set of symbols of the slot.

For a set of symbols of a slot that are indicated as DL/UL by thehigher-layer parameter TDD-UL-DL-ConfigurationCommon, orTDDUL-DL-ConfigDedicated, the UE does not expect to detect DCI format2_0 with an SFI-index field value indicating the set of symbols of theslot as UL/DL, respectively, or as flexible.

For a set of symbols of a slot indicated to the UE by the higher-layerparameter ssb-PositionsInBurst in a higher-layer parameterSystemInformationBlockType1 or ServingCellConfigCommon for reception ofSS/PBCH blocks, the UE does not expect to detect DCI format 2_0 with anSFI-index field value indicating the set of symbols of the slot as UL.

For a set of symbols of a slot indicated to the UE by a higher-layerparameter prach-ConfigurationIndex in a higher-layer parameterRACH-ConfigCommon for PRACH transmissions, the UE does not expect todetect DCI format 2_0 with an SFI-index field value indicating the setof symbols of the slot as DL.

For a set of symbols of a slot indicated to the UE by a higher-layerparameter pdcch-ConfigSIB1 in MIB for a CORESET for a Type0-PDCCH CSSset, the UE does not expect to detect DCI format 2_0 with an SFI-indexfield value indicating the set of symbols of the slot as UL.

For a set of symbols of a slot indicated to the UE as flexible by thehigher-layer parameter TDD-UL-DL-ConfigurationCommon and thehigher-layer parameter TDD-UL-DLConfigDedicated, or when thehigher-layer parameter TDD-UL-DL-ConfigurationCommon and thehigher-layer parameter TDD-UL-DL-ConfigDedicated are not provided to theUE, if the UE detects DCI format 2_0 providing a slot formatcorresponding to a slot format value other than 255,

-   -   if one or more symbols in the set of symbols are symbols in a        CORESET configured for the UE for PDCCH monitoring, the UE        receives a PDCCH in the CORESET only if an SFI-index field value        in DCI format 2_0 indicates that the one or more symbols are DL        symbols.    -   if the SFI-index field value in DCI format 2_0 indicates the set        of symbols of the slot as flexible and the UE detects DCI format        1_0, DCI format 1_1, or DCI format 0_1 indicating to the UE to        receive a PDSCH or a CSI-RS in the set of symbols of the slot,        the UE receives a PDSCH or a CSI-RS in the set of symbols of the        slot.    -   if the SFI-index field value in DCI format 2_0 indicates the set        of symbols of the slot as flexible and the UE detects DCI format        0_0, DCI format 0_1, DCI format 1_0, DCI format 1_1, DCI format        2_3, or an RAR UL grant indicating to the UE to transmit a        PUSCH, a PUCCH, a PRACH, or an SRS in the set of symbols of the        slot, the UE transmits the PUSCH, PUCCH, PRACH, or SRS in the        set of symbols of the slot.        -   if the SFI-index field value in DCI format 2_0 indicates the            set of symbols of the slot as flexible, and the UE does not            detect DCI format 1_0, DCI format 1_1, or DCI format 0_1            indicating to the UE to receive a PDSCH or a CSI-RS, or the            UE does not detect DCI format 0_0, DCI format 0_1, DCI            format 1_0, DCI format 1_1, DCI format 2_3, or an RAR UL            grant indicating to the UE to transmit a PUSCH, a PUCCH, a            PRACH, or an SRS in the set of symbols of the slot, the UE            does not transmit or receive a signal in the set of symbols            of the slot.    -   if the UE is configured by the higher layer to receive a PDSCH        or a CSI-RS in the set of symbols of the slot, the UE receives        the PDSCH or the CSI-RS in the set of symbols of the slot, only        if the SFI-index field value in DCI format 2_0 indicates the set        of symbols of the slot as DL.    -   if the UE is configured by the higher layer to transmit a PUCCH,        a PUSCH, or a PRACH in the set of symbols of the slot, the UE        transmits the PUCCH, or the PUSCH, or the PRACH in the slot only        if the SFI-index field value in DCI format 2_0 indicates the set        of symbols of the slot as UL.    -   if the UE is configured by the higher layer to transmit an SRS        in the set of symbols of the slot, the UE transmits the SRS only        in a subset of symbols from the set of symbols of the slot        indicated as UL symbols by the SFI-index field value in DCI        format 2_0.    -   the UE does not expect to detect an SFI-index field value in DCI        format 2_0 indicating the set of symbols of the slot as DL and        also detect DCI format 0_0, DCI format 0_1, DCI format 1_0, DCI        format 1_1, DCI format 2_3, or an RAR UL grant indicating to the        UE to transmit an SRS, a PUSCH, a PUCCH, or a PRACH, in one or        more symbols from the set of symbols of the slot.    -   the UE does not expect to detect an SFI-index field value in DCI        format 2_0 indicating the set of symbols of the slot as DL or        flexible, if the set of symbols of the slot includes symbols        corresponding to any repetition of a PUSCH transmission        activated by a UL Type 2 grant PDCCH.    -   the UE does not expect to detect an SFI-index field value in DCI        format 2_0 indicating the set of symbols of the slot as UL and        also detect DCI format 1_0 or DCI format 1_1 or DCI format 0_1        indicating to the UE to receive a PDSCH or a CSI-RS in one or        more symbols from the set of symbols of the slot.

If the UE is configured by the higher layer to receive a CSI-RS or aPDSCH in a set of symbols of a slot and detects DCI format 2_0indicating a subset of symbols from the set of symbols as UL or flexibleor DCI format 0_0, DCI format 0_1, DCI format 1_0, DCI format 1_1, orDCI format 2_3 indicating to the UE to transmit a PUSCH, a PUCCH, anSRS, or a PRACH in at least one symbol in the set of the symbols, the UEcancels the CSI-RS reception or the PDSCH reception in the slot.

If the UE is configured by the higher layer to transmit an SRS, a PUCCH,or a PUSCH, or a PRACH in a set of symbols of a slot and detects DCIformat 2_0 with a slot format value indicating a subset of symbols fromthe set of symbols as DL or flexible, or DCI format 1_0, DCI format 1_1,or DCI format 0_1 indicating to the UE to receive a CSI-RS or a PDSCH inat least one symbol in the set of symbols, then

-   -   the UE does not expect to cancel the signal transmission in the        subset of symbols that occur, relative to a last symbol of a        CORESET in which the UE detects DCI format 2_0, DCI format 1_0,        DCI format 1_1, or DCI format 0_1, after fewer symbols than a        PUSCH preparation time T_(proc,2) for the corresponding PUSCH        processing capability.    -   the UE cancels the PUCCH, or PUSCH, or PRACH transmission in the        remaining symbols in the set of symbols and cancels the SRS        transmission in the remaining symbols in the set of symbols.

If the UE does not detect DCI format 2_0 indicating the set of symbolsof the slot as flexible or UL or DCI format 0_0, DCI format 0_1, DCIformat 1_0, DCI format 1_1, or DCI format 2_3 indicating to the UE totransmit an SRS, a PUSCH, a PUCCH, or a PRACH in the set of symbols, theUE assumes that flexible symbols in a CORESET configured for the UE forPDCCH monitoring are DL symbols.

For a set of symbols of a slot that are indicated as flexible by thehigher-layer parameters TDD-UL-DL-ConfigurationCommon andTDD-UL-DLConfigDedicated, or when the higher-layer parametersTDD-UL-DL-ConfigurationCommon, and TDD-UL-DL-ConfigDedicated are notprovided to the UE, if the UE does not detect DCI format 2_0 providing aslot format for the slot,

-   -   the UE receives a PDSCH or a CSI-RS in the set of symbols of the        slot, if the UE receives a corresponding indication by DCI        format 1_0, DCI format 1_1, or DCI format 0_1.    -   the UE transmits a PUSCH, a PUCCH, a PRACH, or an SRS in the set        of symbols of the slot, if the UE receives a corresponding        indication by DCI format 0_0, DCI format 0_1, DCI format 1_0,        DCI format 1_1, or DCI format 2_3.    -   the UE may receive a PDCCH.    -   if the UE is configured by the higher layer to receive a PDSCH        or a CSI-RS in the set of symbols of the slot, the UE does not        receive the PDSCH or the CSI-RS in the set of symbols of the        slot.    -   if the UE is configured by the higher layer to transmit an SRS,        a PUCCH, a PUSCH, or a PRACH in the set of symbols of the slot,        -   the UE does not transmit the PUCCH, the PUSCH, or the PRACH            in the slot and does not transmit the SRS in symbols from            the set of symbols in the slot, if any, starting from a            symbol that is a number of symbols equal to the PUSCH            preparation time N2 for the corresponding PUSCH timing            capability after a last symbol of a CORESET where the UE is            configured to monitor PDCCH for DCI format 2_0.    -   The UE does not expect to cancel the transmission of the SRS, or        the PUCCH, or the PUSCH, or the PRACH in symbols from the set of        symbols in the slot, if any, starting before a symbol that is a        number of symbols equal to the PUSCH preparation time N₂ for the        corresponding PUSCH timing capability after a last symbol of a        CORESET where the UE is configured to monitor a PDCCH for DCI        format 2_0.

1.6. Dynamic Slot Format Indication Information (e.g., DCI Format 2_0)

Basically, a slot format indicates the usage of each symbol in a slot.The slot format indicates each symbol as DL (D), UL (U), or flexible(F). Slot format-related information may be transmitted in one or moreof the following signals:

-   -   a static or semi-static slot format indication (SFI) (e.g.,        TDD-UL-DL-ConfigurationCommon and/or TDD-UL-DL-ConfigDedicated)        by higher-layer signaling    -   a measurement-related scheduling signal (e.g., a        measurement-related signal configured by UE-specific RRC        signaling)    -   a dynamic SFI (e.g., a signal transmitted in DCI format 2_0)    -   a UE-specific data transmission scheduling signal (e.g.,        UE-specific DCI)

The static or semi-static SFI may be indicated by cell-specific RRCsignaling (e.g., TDD-UL-DL-ConfigurationCommon) or UE-specific RRCsignaling (e.g., TDD-UL-DL-ConfigDedicated). The measurement-relatedsignal may be indicated by UE-specific RRC signaling, and thecorresponding signal may indicate a periodic/semi-persistent CSI-RS, aperiodic CSI report, a periodic/semi-persistent SRS, or the like. TheUE-specific data transmission-related signal may include UE-specific DCIthat triggers a PUCCH along with an A/N for a PDSCH, a PUSCH, or aPDSCH, and DCI that triggers an aperiodic measurement-related signalsuch as an aperiodic CSI-RS, an aperiodic SRS, or the like.

FIGS. 13A to 13C are diagrams illustrating exemplary slot formatsaccording to various embodiments of the present disclosure. Morespecifically, FIGS. 13A to 13C illustrate an exemplary slot format foreach number of switching points according to various embodiments of thepresent disclosure.

The slot formats include a format for zero, one or two switching points.FIGS. 13A to 13C illustrate various exemplary slot formats.Specifically, FIG. 13A illustrates an exemplary slot format for zeroswitching point, FIG. 13B illustrates an exemplary slot format for oneswitching point, and FIG. 13C illustrates an exemplary slot format fortwo switching points.

The slot format for zero switching point includes 14 DL symbols, 14flexible symbols, or 14 UL symbols. The slot format for one switchingpoint is configured to start with zero or more DL symbols and end withzero or more UL symbols, with one or more flexible symbols and DL/ULsymbols in between. The slot format for two switching points isconfigured to include first 7 symbols starting with zero or more DLsymbols and ending with one or more UL symbols in a 7^(th) symbol, andsecond 7 symbols starting with one or more DL symbols and ending withzero or more UL symbols. Each of the sets of the first 7 symbols and thesecond 7 symbols may include zero or more flexible symbols.

Up to 256 such slot formats may be defined, and their configurations aredefined in the technical specification TS 38.211 and so on. The UE isconfigured with a UE-specific SFI table based on the up to 256 slotformats by higher-layer signaling, and receives a specific index valueof the UE-specific SFI table in DCI format 2_0 (or a GC-PDCCH).

The UE determines a slot format based on the following prioritizationfor signals carrying the above-described slot format-relatedinformation. More specifically, when the UE receives slot format-relatedinformation in a plurality of signals, the UE considers indicationinformation of signals with the following priority only to identify theusage of a symbol indicated as flexible by a high-priority signal.

Slot format information by cell-specific higher-layer signaling (e.g.,TDD-UL-DL-ConfigurationCommon)>slot format information by UE-specifichigher-layer signaling (e.g., TDD-UL-DL-ConfigDedicated)>slot formatinformation by a GC-PDCCH (e.g., DCI format 2_0)>UE-specific datatransmission scheduling information>measurement-related schedulinginformation

Therefore, when a specific symbol in a slot is indicated to the UE asDL/UL by cell-specific RRC signaling or UE-specific RRC signaling, theUE does not expect DCI format 2_0 (or a group-specific PDCCH includingDCI format 2_0) to indicate the specific symbol as UL/DL or flexible.When a specific symbol in a slot is indicated as flexible by DCI format2_0 (or a group-specific PDCCH including DCI format 2_0), the UEtransmits and receives a related signal in the specific symbol only whenseparately receiving scheduling information (e.g., UE-specificscheduling DCI). When the UE does not receive the scheduling informationseparately, the UE does not transmit/receive a signal in the specificsymbol.

1.7. DL Preemption-Related Information (e.g., DCI Format 2_1)

The wireless communication system to which various embodiments of thepresent disclosure are applied supports eMBB transmission with arelatively large traffic size and URLLC transmission with a relativelysmall traffic size.

FIGS. 14A and 14B are diagrams illustrating exemplary resource sharingbetween an eMBB transmission and a URLLC transmission according tovarious embodiments of the present disclosure.

When an eMBB transmission and a URLLC transmission have the sametransmission duration, the eMBB transmission and the URLLC transmissionmay share non-overlapped time/frequency resources based on scheduling,as illustrated in FIG. 14A. Alternatively, in DL transmission, a URLLCtransmission may occur in resources for an on-going eMBB transmission,to satisfy different latency and/or reliability requirements for theeMBB transmission and the URLLC transmission.

For this purpose, DCI format 2_1 delivers information about resources(partially) overlapped with scheduled resources for a DL eMBBtransmission to the UE (for a URLLC transmission). The UE assumes thatthere is no signal transmission in an RB and a symbol indicated by DCIformat 2_1. The UE may exclude indicated coded bits from a soft bufferand (re)decode a PDSCH, referring to a DL preemption indication.

FIG. 15 is a diagram illustrating an exemplary DL preemption indicationaccording to various embodiments of the present disclosure. Morespecifically, FIG. 15 is a diagram illustrating a configuration ofindicating URLLC transmission resources overlapped with preconfigured DLeMBB resources by a DL preemption indication according to variousembodiments of the present disclosure.

FIG. 16 is a diagram illustrating an exemplary preemption operationaccording to various embodiments of the present disclosure. Morespecifically, FIG. 16 illustrates an exemplary operation of preemptingsome resources by a PI in DCI format 2_1 according to variousembodiments of the present disclosure.

The BS transmits a DL preemption indication in DCI format 2_1 to UE(s).DCI format 2_1 indicates preempted resources in a referencetime/frequency resource area. The monitoring periodicity of DCI format2_1 including a preemption indication (PI) may be equal to theperiodicity of the reference time area. The reference frequency area maybe identical to an active DL BWP.

FIGS. 17A and 17B are diagrams illustrating an exemplary method ofrepresenting preemption indication information as a bitmap according tovarious embodiments of the present disclosure.

The time/frequency granularity of the preemption indication informationis determined by timeFrequencySet in higher-layer signalingDownlinkPreemption.

When the value of timeFrequencySet is 0 (Set0), DL resources forpreemption indication are divided into 14 time-domain parts or groups(e.g., each group includes consecutive symbols), and each bit indicatesthe presence or absence of a transmission to the UE in a correspondingtime-domain part or group (e.g., when the value of a bit is 1, thisindicates the presence of a signal transmission for the UE, and when thevalue of a bit is 0, this indicates the absence of a signal transmissionfor the UE, as illustrated in FIG. 17A).

When the value of timeFrequencySet is 1 (Set1), DL resources forpreemption indication are divided into 7 time-domain parts or pairs(e.g., each group includes consecutive symbols). The first bit of eachpair indicates the presence or absence of a signal transmission to theUE in some frequency-domain part of a corresponding time-domain part orpair, and the second bit of the pair indicates the presence or absenceof a signal transmission to the UE in the remaining frequency-domainparts of the corresponding time-domain part or pair (e.g., when thevalue of a bit is 1, this indicates the presence of a signaltransmission in a corresponding time/frequency area for the UE, and whenthe value of a bit is 0, this indicates the absence of a signaltransmission in the time/frequency area for the UE, as illustrated FIG.17B).

1.8. Multiplexing of Short PUCCH and Long PUCCH

FIG. 18 illustrates exemplary multiplexing between a UL signal and shortand long PUCCHs according to various embodiments of the presentdisclosure.

A PUCCH (e.g., PUCCH format 0/2) and a PUSCH may be multiplexed in TDMor FDM. A short PUCCH and a long PUCCH from different UEs may bemultiplexed in TDM or FDM. Short PUCCHs from a single UE may bemultiplexed in TDM within one slot. A short PUCCH and a long PUCCH froma single UE may be multiplexed in TDM or FDM within one slot.

2. Unlicensed Band/Shared Spectrum System

FIGS. 19A and 19B are diagrams illustrating an exemplary wirelesscommunication system supporting an unlicensed band to which variousembodiments of the present disclosure are applicable.

In the following description, a cell operating in a licensed band(L-band) is defined as an L-cell, and a carrier of the L-cell is definedas a (DL/UL) LCC. Further, a cell operating in an unlicensed band(U-band) is defined as a U-cell, and a carrier of the U-cell is definedas a (DL/UL) UCC. The carrier/carrier-frequency of a cell may refer tothe operating frequency (e.g., center frequency) of the cell. Acell/carrier (e.g., CC) is generically referred to as a cell.

When a UE and a BS transmit and receive signals to and from each otherin a carrier-aggregated LCC and UCC, the LCC may be configured as aprimary CC (PCC), and the UCC may be configured as a secondary CC (SCC),as illustrated in FIG. 19A.

As illustrated in FIG. 19B, the UE and the BS may transmit and receivesignals to and from each other in one UCC or a plurality ofcarrier-aggregated LCCs and UCCs. That is, the UE and the BS maytransmit and receive signals only in UCC(s) without an LCC. (Unlessotherwise mentioned) a signal transmission and reception operation in anunlicensed band as described in various embodiments of the presentdisclosure may be performed based on all of the above-describeddeployment scenarios.

2.1. Radio Frame Structure for Unlicensed Band

For an operation in an unlicensed band, frame structure type 3 of LTE(see FIG. 3 ) or an NR frame structure (see FIG. 7 ) may be used. Theconfiguration of OFDM symbols occupied by a UL/DL signal transmission ina frame structure for the unlicensed band may be configured by the BS.Herein, the term OFDM symbol may be replaced with SC-FDM(A) symbol.

For a DL signal transmission in the unlicensed band, the BS may indicatethe configuration of OFDM symbols used in subframe #n to the UE bysignaling. In the following description, the term subframe may bereplaced with slot or time unit (TU).

Specifically, in the wireless communication system supporting theunlicensed band, the UE may assume (or identify) the configuration ofOFDM symbols occupied in subframe #n by a specific field (e.g., aSubframe configuration for LAA field or the like) in DCI received insubframe #n−1 or subframe #n from the BS.

Table 15 illustrates an exemplary method of representing theconfiguration of occupied OFDM symbols for transmission of a DL physicalchannel and/or physical signal in a current subframe and/or nextsubframe by the Subframe configuration for LAA field in the wirelesscommunication system.

TABLE 15 Value of ‘Subframe Configuration of occupied configuration forLAA’ OFDM symbols (current field in current subframe subframe, nextsubframe) 0000 (—, 14) 0001 (—, 12) 0010 (—, 11) 0011 (—, 10) 0100 (—,9)  0101 (—, 6)  0110 (—, 3)  0111 (14, *)  1000 (12, —) 1001 (11, —)1010 (10, —) 1011  (9, —) 1100  (6, —) 1101  (3, —) 1110 reserved 1111reserved NOTE: (—, Y) means UE may assume the first Y symbols areoccupied in next subframe and other symbols in the next subframe are notoccupied. (X, —) means UE may assume the first X symbols are occupied incurrent subframe and other symbols in the current subframe are notoccupied. (X, *) means UE may assume the first X symbols are occupied incurrent subframe, and at least the first OFDM symbol of the nextsubframe is not occupied.

For a UL signal transmission in the unlicensed band, the BS may transmitinformation about a UL transmission duration to the UE by signaling.

Specifically, in an LTE system supporting an unlicensed band, the UE mayacquire ‘UL duration’ and ‘UL offset’ information for subframe #n by a‘UL duration and offset’ field in detected DCI.

Table 16 illustrates an exemplary method of representing a UL offset andUL duration configuration by the UL duration and offset field in thewireless communication system.

TABLE 16 Value of ‘UL duration UL offset, l UL duration, d and offset’field (in subframes) (in subframes) 00000 Not configured Not configured00001 1 1 00010 1 2 00011 1 3 00100 1 4 00101 1 5 00110 1 6 00111 2 101000 2 2 01001 2 3 01010 2 4 01011 2 5 01100 2 6 01101 3 1 01110 3 201111 3 3 10000 3 4 10001 3 5 10010 3 6 10011 4 1 10100 4 2 10101 4 310110 4 4 10111 4 5 11000 4 6 11001 6 1 11010 6 2 11011 6 3 11100 6 411101 6 5 11110 6 6 11111 reserved reserved

For example, when the UL duration and offset field configures (orindicates) UL offset 1 and UL duration d for subframe #n, the UE doesnot need to receive a DL physical channel and/or physical signal insubframe #n+1+i (i=0, 1, . . . , d−1).

2.2 Overview of Channel Access Procedures (CAPs)

Unless otherwise noted, the definitions below are applicable for thefollowing terminologies used in the present disclosure.

-   -   A channel refers to a carrier or a part of a carrier composed of        a contiguous set of RBs in which a CAP is performed in a shared        spectrum.    -   A channel access procedure (CAP) may be a procedure based on        sensing that evaluates the availability of a channel for        performing transmissions. A basic unit for sensing is a sensing        slot with a duration of T_(sl)=9 us. The sensing slot duration        may be considered to be idle if an eNB/gNB or a UE senses the        channel during the sensing slot duration, and determines that        the detected power for at least 4 us within the sensing slot        duration is less than an energy detection threshold X_(Thresh).        Otherwise, the sensing slot duration T_(sl) may be considered to        be busy.    -   Channel occupancy refers to transmission(s) on channel(s) by        eNB/gNB/UE(s) after performing a corresponding CAP in this        subclause.    -   A channel occupancy time (COT) refers to the total time for        which eNB/gNB/UE(s) and any eNB/gNB/UE(s) sharing the channel        occupancy perform transmission(s) on a channel after an        eNB/gNB/UE performs the corresponding CAPs described in this        subclause. For determining a COT, if a transmission gap is less        than or equal to 25 us, the gap duration may be counted in the        COT. The COT may be shared for transmission between an eNB/gNB        and corresponding UE(s).    -   A DL transmission burst is defined as a set of transmissions        from an eNB/gNB without any gaps greater than 16 us.        Transmissions from an eNB/gNB separated by a gap of more than 16        us are considered as separate DL transmission bursts. An eNB/gNB        may transmit transmission(s) after a gap within a DL        transmission burst without sensing the corresponding channel(s)        for availability.    -   A UL transmission burst is defined as a set of transmissions        from a UE without any gap greater than 16 us. Transmissions from        a UE separated by a gap of more than 16 us are considered as        separate UL transmission bursts. A UE may transmit        transmission(s) after a gap within a UL transmission burst        without sensing the corresponding channel(s) for availability.    -   A discovery burst refers to a DL transmission burst including a        set of signal(s) and/or channel(s) confined within a window and        associated with a duty cycle. The discovery burst may be any of        the following:        -   Transmission(s) initiated by an eNB that includes a primary            synchronization signal (PSS), secondary synchronization            signal (SSS) and cell-specific reference signal(s) (CRS) and            may include non-zero power CSI-RS.        -   Transmission(s) initiated by a gNB that includes at least an            SS/PBCH block and may also include a CORESET for a PDCCH            scheduling a PDSCH with SIB1, and a PDSCH carrying SIB1            and/or non-zero power CS-RS. The SS/PBCH block may include a            PSS, a SSS, and a PBCH with an associated demodulation            reference signal (DM-RS).

2.3. Downlink Channel Access Procedures (DL CAPs)

For a DL signal transmission in an unlicensed band, the BS may perform aDL CAP for the unlicensed band as follows. On the assumption that aPCell being a licensed band and one or more SCells being an unlicensedband are basically configured for the BS, the following description isgiven of DL CAPs to which various embodiments of the present disclosureare applicable, in which an unlicensed band is referred to as a licensedassisted access (LAA) SCell. However, the DL CAPs may also be applied inthe same manner, when only an unlicensed band is configured for the BS.

2.3.1. Type 1 DL Channel Access Procedures

This subclause describes CAPs to be performed by a BS for which a timeduration spanned by sensing slots that are sensed to be idle before DLtransmission(s) is random. This subclause is applicable to the followingtransmissions:

-   -   Transmission(s) initiated by a BS including a        PDSCH/PDCCH/EPDCCH, or    -   Transmission(s) initiated by a BS including a unicast PDSCH with        user plane data, or a unicast PDSCH with user plane data and a        unicast PDCCH scheduling user plane data, or    -   Transmission(s) initiated by a BS with only a discovery burst or        with a discovery burst multiplexed with non-unicast information,        where the duration of the transmission(s) is larger than 1 ms or        the transmission causes the discovery burst duty cycle to exceed        1/20.

The BS may perform a transmission after sensing the channel to be idleduring the sensing slot durations of a defer duration T_(d) and after acounter N is zero in step 4 described below. The counter N is adjustedby sensing the channel for an additional sensing slot duration accordingto the following procedure:

-   -   1) set N=N_(init) where N_(init) is a random number uniformly        distributed between 0 and CW_(p), and go to step 4;    -   2) if N>0 and the BS chooses to decrement the counter, set        N=N−1;    -   3) sense the channel for an additional sensing slot duration,        and if the additional sensing slot duration is idle, go to step        4; else, go to step 5;    -   4) if N=0, stop: else, go to step 2;    -   5) sense the channel until either a busy sensing slot is        detected within an additional deter duration T_(d) or all the        sensing slots of the additional defer duration T_(d) are        detected to be idle; and    -   6) if the channel is sensed to be idle during all the sensing        slot durations of the additional defer duration T_(d), go to        step 4; else, go to step 5.

FIG. 20 is a flowchart illustrating a DL CAP for transmission in anunlicensed band, to which various embodiments of the present disclosureare applicable.

The afore-described Type 1 DL CAP may be summarized as follows.

For a DL transmission, a transmission node (e.g., a BS) may initiate aCAP (2010).

The BS may randomly select a backoff counter N within a contentionwindow (CW) according to step 1. N is set to an initial value N_(init)(2020). N_(init) is a random value selected between 0 and CW_(p).

Subsequently, when the backoff counter value N is 0 according to step 4(2030; Y), the BS terminates the CAP (2032). The BS may then perform aTx burst transmission (2034). On the contrary, when the backoff countervalue N is not 0 (2030; N), the BS decrements the backoff counter valueby 1 according to step 2 (2040).

Subsequently, the BS checks whether the channel is idle (2050). If thechannel is idle (2050; Y), the BS determines whether the backoff countervalue is 0 (2030).

On the contrary, when the channel is not idle, that is, the channel isbusy in operation 2050 (2050; N), the BS determines whether the channelis idle during a longer defer duration T_(d) (25 usec or longer) than asensing slot duration (e.g., 9 usec) (2060). If the channel is idleduring the deter duration (2070; Y), the BS may resume the CAP.

For example, when the backoff counter value N_(init) is 10 and thechannel is determined to be idle after the backoff counter value isdecremented to 5, the BS senses the channel during the defer durationand determines whether the channel is idle. If the channel is idleduring the defer duration, the BS may resume the CAP from the backoffcounter value 5 (or from the backoff counter value 4 obtained bydecrementing the backoff counter value 5 by 1), instead of setting thebackoff counter value N_(init).

On the other hand, when the channel is busy during the defer duration(2070; N), the BS determines again whether the channel is idle during anew defer duration by performing step 2060 again.

If the BS has not performed a transmission after step 4 in the aboveprocedure, the BS may perform a transmission on the channel, if thefollowing condition is satisfied:

if the BS is ready to transmit and the channel is sensed to be idle atleast in a sensing slot duration T_(sl), and if the channel has beensensed to be idle during all the sensing slot durations of a deferduration T_(d) immediately before this transmission.

On the contrary, if the channel has not been sensed to be idle in thesensing slot duration T_(sl) when the BS first senses the channel afterit is ready to transmit or if the channel has not been sensed to be idleduring any of the sensing slot durations of the defer duration T_(d)immediately before this intended transmission, the BS proceeds to step 1after sensing the channel to be idle during the sensing slot durationsof the defer duration T_(sl).

The defer duration T_(d) includes a duration T_(f)(=16 us) immediatelyfollowed by m_(p) consecutive sensing slot durations. Each sensing slotduration T_(sl) is 9 us and the duration T_(f) includes an idle sensingslot duration T_(sl) at the start of the duration T_(f).

CW_(min , p) ≤ CW_(p)≤ CW_(max , p)is the contention window. CW_(p) adjustment is described in subclause2.2.3.

CW_(min , p)  and  CW_(max , p)are chosen before step 1 of the above procedure.

m_(p), CW_(min , p)  and  CW_(max , p)are determined based on a channel access priority class associated withthe BS transmission (refer to Table 17).

X_(Thresh) is adjusted according to subclause 2.3.4. as described later.

TABLE 17 Channel Access Priority allowed Class (p) m_(p) CW_(min, p)CW_(max, p) T_(mcot, p) CW_(p) sizes 1 1 3 7 2 ms {3, 7} 2 1 7 15 3 ms{7, 15} 3 3 15 63 8 or 10 ms {15, 31, 63} 4 7 15 1023 8 or 10 ms {15,31, 63, 127, 255, 511, 1023}

If N>0 in the above procedure, when the BS transmits discovery burst(s),the BS does not decrement the counter N during the sensing slotduration(s) overlapping with the discovery burst(s).

The BS may use any channel access priority class for performing theabove procedures to perform transmission(s) including discovery burst(s)satisfying the conditions described in this subclause.

The BS should use a channel access priority class applicable to unicastuser plane data multiplexed in a PDSCH for performing the aboveprocedures to perform transmission(s) including a unicast PDSCH withuser plane data.

For p=3 and p=4 in Table 13, if the absence of any other technologysharing the channel may be guaranteed on a long term basis (e.g. bylevel of regulation), T_(mcot,p) is set to 10 ms. Otherwise, T_(mcot,p)is set to 8 ms.

2.3.2. Type 2 DL Channel Access Procedures

This subclause describes CAPs to be performed by the BS, for which atime duration spanned by sensing slots that are sensed to be idle beforeDL transmission(s) is deterministic.

Type 2A DL CAPs may be applied to the following transmission(s)performed by the BS.

-   -   Transmission(s) initiated by a BS, including a discovery burst        and not including a PDSCH, or    -   transmission(s) initiated by a BS, with only a discovery burst        or with a discovery burst multiplexed with non-unicast        information. Herein, the transmission duration is at most 1 ms,        or the transmission causes the discovery burst duty cycle to        exceed 1/20. Alternatively,    -   transmission(s) of a BS, following transmission(s) of a UE after        a gap of 25 us in a shared channel occupancy.

Type 2B or Type 2C DL CAPs are applicable to transmission(s) performedby a BS, following transmission(s) of a UE after a gap of 16 us or up to16 us, respectively, in a shared channel occupancy.

2.3.2.1. Type 2A DL Channel Access Procedure

The BS may perform a DL transmission immediately after sensing thechannel to be idle for at least a sensing duration T_(short dl)=25 us.T_(short dl) include a duration T_(f)(=16 us) following one sensing slotduration. T_(f) includes a sensing slot at the start of T_(f). If bothsensing slots of T_(short dl) are sensed to be idle, the channel isconsidered to be idle for T_(short dl).

2.3.2.2. Type 2B DL Channel Access Procedure

The BS may perform a DL transmission immediately after sensing thechannel to be idle for a duration of T_(f)=16 us. T_(f) includes asensing slot that occurs within the last 9 us of T_(f). The channel isconsidered to be idle within the duration T_(f), if the channel issensed to be idle for a total of 5 us at least with at least of 4 ussensing occurring in the sensing slot, the channel is considered to beidle for T_(f).

2.3.2.3. Type 2C DL Channel Access Procedure

When the BS follows the procedure in this subclause, for a DLtransmission, the BS does not sense the channel before the DLtransmission. The duration of the corresponding DL transmission is atmost 584 us.

2.3.3. Contention Window Adjustment Procedures

If the BS performs a transmission including a PDSCH that is associatedwith a channel access priority class p on a channel, the BS maintains acontention window value CW_(p) and adjusts the contention widow valueCW_(p) before step 1 of the procedure described in subclause 2.3.1. forthe transmission.

2.3.3.1. Contention Window Adjustment Procedures for Transmissions byeNB

If an eNB performs a transmission including a PDSCH that is associatedwith a channel access priority class p on a channel, the eNB maintains acontention window value CW_(p) and adjusts CW_(p) before step 1 of theprocedure described in subclause 2.3.1. (i.e., before a CAP isperformed) for the transmission using the following steps.

1> For every priority class

p ∈ {1, 2, 3, 4}, set  CW_(p) = CW_(min , p).

2> if at least Z=80% of HARQ-ACK values corresponding to PDSCHtransmission(s) in a reference subframe k are determined as NACK,increase CW_(p) for every priority class p∈{1, 2, 3, 4} to the nexthigher allowed value and remain in step 2; otherwise, go to step 1.

In other words, if the probability of HARQ-ACK values corresponding toPDSCH transmission(s) in reference subframe k being determined as NACKis at least 80%, the eNB increases a CW value set for each priorityclass to the next higher allowed value. Alternatively, the eNB maintainsthe CW value set for each priority class to be an initial value.

Reference subframe k is the starting subframe of the most recenttransmission on the channel made by the eNB, for which at least someHARQ-ACK feedback is expected to be available.

The eNB adjusts the value CW_(p) of for every priority class p∈{1, 2, 3,4} based on a given reference subframe k only once.

The probability Z of HARQ-ACK values corresponding to PDSCHtransmission(s) in reference subframe k being determined as NACK may bedetermined in consideration of the following.

-   -   If the eNB transmission(s) for which HARQ-ACK feedback is        available starts in the second slot of the subframe k, HARQ-ACK        values corresponding to PDSCH transmission(s) in subframe k+1        are also used in addition to the HARQ-ACK values corresponding        to PDSCH transmission(s) in the subframe k.    -   If the HARQ-ACK values correspond to PDSCH transmission(s) on an        LAA SCell that are assigned by an (E)PDCCH transmitted on the        same LAA SCell,        -   if no HARQ-ACK feedback is detected for a PDSCH transmission            by the eNB or if the eNB detects ‘DTX’, ‘NACK/DTX’ or ‘any’            state, it is counted as NACK.    -   If the HARQ-ACK values correspond to PDSCH transmission(s) on        another LAA SCell that are assigned by an (E)PDCCH transmitted        on an LAA SCell,        -   if the HARQ-ACK feedback for a PDSCH transmission is            detected by the eNB, ‘NACK/DTX’ or ‘any’ state is counted as            NACK, and ‘DTX’ state is ignored.        -   If no HARQ-ACK feedback is detected for a PDSCH transmission            by the eNB,            -   if PUCCH format 1 with channel selection is expected to                be used by the eNB, ‘NACK/DTX’ state corresponding to                ‘no transmission’ is counted as NACK, and ‘DTX’ state                corresponding to ‘no transmission’ is ignored.            -   Otherwise, the HARQ-ACK for the PDSCH transmission is                ignored.    -   If a PDSCH transmission has two codewords, the HARQ-ACK value of        each codeword is considered separately.    -   A bundled HARQ-ACK across M subframes is considered as M        HARQ-ACK responses.

If the eNB performs a transmission including a PDCCH/EPDCCH with DCIformat 0A/0B/4A/4B and not including a PDSCH associated with a channelaccess priority class p on a channel starting from time t₀, the eNBmaintains the contention window value CW_(p) and adjusts CW_(p) beforestep 1 of the procedure described in subclause 2.3.1. for thetransmission using the following steps.

1> For every priority class p∈{1, 2, 3, 4}, set CW_(p)=CW_(min,p).

2> If less than 10% of UL transport blocks scheduled by the eNB usingthe Type 2 CAP (described in subclause 2.3.1.2) in the time durationbetween t₀ and t₀+T_(CO) have been received successfully, increaseCW_(p) for every priority class p∈{1, 2, 3, 4} to the next higherallowed value and remain in step 2; otherwise, go to step 1.

T_(CO) is computed as described in subclause 2.3.1, which will bedescribed below.

If CW_(p)=CW_(max,p) is used K times consecutively to generate N_(init),only CW_(p) for a priority class p for

CW_(p) = CW_(max , p)used K times consecutively is reset to CW_(min,p). K is selected from aset of values {1, 2, . . . , 8} for every priority class p∈{1, 2, 3, 4}by the eNB.

2.3.3.2. Contention Window Adjustment Procedures for DL Transmissions bygNB

If a gNB performs a transmission including a PDSCH that is associatedwith a channel access priority class p on a channel, the gNB maintains acontention window value CW_(p) and adjusts CW_(p) before step 1 of theprocedure described in subclause 2.3.1. (i.e., before a CAP isperformed) for the transmission using the following steps.

1> For every priority class p∈{1, 2, 3, 4}, set CW_(p)=CW_(min,p).

2> If HARQ-ACK feedback is available after the last update of CW_(p), goto step 3. Otherwise, if the gNB transmission after the proceduredescribed in subclause 2.3.1 does not include a retransmission or isperformed within a duration T_(w) from the end of a reference durationcorresponding to the earliest DL transmission burst after the lastupdate of CW_(p) transmitted after the procedure described in subclause2.3.1, go to step 5; otherwise go to step 4.

3> The HARQ-ACK feedback(s) corresponding to PDSCH(s) in the referenceduration for the latest DL transmission burst for which HARQ-ACKfeedback is available is used as follows.

a. If at least one HARQ-ACK feedback is ‘ACK’ for PDSCH(s) with TB-basedtransmissions or at least 10% of HARQ-ACK feedbacks is ‘ACK’ forPDSCH(s) with CBG-based transmissions, go to step 1; otherwise go tostep 4.

4> Increase CW_(p) for every priority class p∈{1, 2, 3, 4} to the nexthigher allowed value.

5> For every priority class p∈{1, 2, 3, 4}, maintain CW_(p) as it is; goto step 2.

The reference duration and the duration Tw in the above procedure aredefined as follows.

-   -   The reference duration corresponding to a channel occupancy        initiated by the gNB, including transmission of PDSCH(s) is        defined in this subclause as a duration starting from the        beginning of the channel occupancy until the end of the first        slot in which at least one unicast PDSCH is transmitted over all        the resources allocated for the PDSCH, or until the end of the        first transmission burst by the gNB that contains unicast        PDSCH(s) transmitted over all the resources allocated for the        PDSCH, whichever occurs earlier. If the channel occupancy        includes a unicast PDSCH, but it does not include any unicast        PDSCH transmitted over all the resources allocated for that        PDSCH, then, the duration of the first transmission burst from        the gNB within the channel occupancy that contains unicast        PDSCH(s) is the reference duration for CWS adjustment.    -   T_(w)=max(T_(A), T_(B)+1 ms) where T_(B) is the duration of the        transmission burst from the start of the reference duration in        ms, If the absence of any other technology sharing the channel        may not be guaranteed on a long-term basis, T_(A)=5 ms, and        otherwise, T_(A)=10 ms.

If the gNB performs a transmission using the Type 1 CAP associated witha channel access priority class p on a channel and the transmission isnot associated with an explicit HARQ-ACK feedback by the correspondingUE(s), the gNB adjusts CW_(p) before step 1 in the procedure describedin subclause 2.3.1., using the latest CW_(p) used for any DLtransmission on the channel using the Type 1 CAP associated with thechannel access priority class p. If the corresponding channel accesspriority class p has not been used for any DL transmission on thechannel, CW_(p)=CW_(min,p) is used.

2.3.3.3. Common Procedures for CWS Adjustments for DL Transmissions

The following applies to the procedures described in subclauses 2.3.3.1.and 2.3.3.2.

-   -   If

CW_(p) = CW_(max , p),the next higher allowed value for adjusting CW_(p) is CW_(max,p).

-   -   If

CW_(p) = CW_(max , p)is consecutively used K times for generation of N_(init), CW_(p) isreset to CW_(min) only for that priority class p for which

CW_(p) = CW_(max , p)is consecutively used K times for generation of N_(init). K is selectedby the eNB/gNB from the set of values {1, 2, . . . , 8} for eachpriority class p∈{1, 2, 3, 4}.

2.3.4. Energy Detection Threshold Adaptation Procedure

An eNB/gNB accessing a channel on which transmission(s) are performedsets an energy detection threshold X_(Thresh) to be less than or equalto a maximum energy detection threshold X_(Thresh_max).

The maximum energy detection threshold X_(Thresh_max) is determined asfollows.

-   -   If the absence of any other technology sharing the channel may        be guaranteed on a long-term basis (e.g. by level of regulation)        then:

$X_{{Thresh}\_\max} = {\min\begin{Bmatrix}{{T_{\max} + {10\; d\; B}},} \\X_{r}\end{Bmatrix}}$

-   -   X_(r) is a maximum energy detection threshold in dBm defined by        regulatory requirements, when such requirements are defined, and        otherwise X_(r)=T_(max)+10 dB.    -   Otherwise,

$X_{{Thres}\_\max} = {\max\begin{Bmatrix}{{{- 72} + {{10 \cdot \log}\; 10\left( {{BW}\;{{MHz}/20}\mspace{11mu}{MHz}} \right){dBM}}},} \\{\min\begin{Bmatrix}{T_{\max},} \\\begin{matrix}{T_{\max} - T_{A} +} \\\left( {P_{H} + {{10 \cdot \log}\; 10\left( {{BW}\mspace{11mu}{{MHz}/20}\mspace{11mu}{MHz}} \right)} - P_{TX}} \right)\end{matrix}\end{Bmatrix}}\end{Bmatrix}}$

where each parameter is defined as follows:

-   -   T_(A)=10 dB for transmission(s) including PDSCH;    -   T_(A)=5 dB for transmission including discovery burst(s) as        described in subclause 4.1.2;    -   P_(H)=23 dBm dBm;    -   P_(TX) is the set maximum eNB/gNB output power in dBm for the        channel:        -   eNB/gNB uses the set maximum transmission power over a            single channel irrespective of whether single channel or            multi-channel transmission is employed    -   T_(max)(dBm)=10·log 10 (3.16228·10⁻⁸ (mW/MHz)·BWMHz (MHz));    -   BWMHz is the single channel bandwidth in MHz.

2.3.5. Channel Access Procedure for Transmission(s) on Multiple Channels

An eNB/gNB may access multiple channels on which transmission(s) areperformed, according to one of the Type A or Type B procedures describedbelow.

2.3.5.1. Type A Multi-Channel Access Procedure

An eNB/gNB performs channel access on each channel c_(i)∈C according tothe procedure described in this subclause. Herein, C is a set ofchannels on which the eNB/gNB intends to transmit, and i=0, 1, . . . q−1where q is the number of channels on which the eNB/gNB intends totransmit.

The counter N described in subclause 2.3.1. (i.e., the counter Nconsidered in a CAP) is determined for each channel c_(i) and is denotedas N_(c) _(i) . N_(c) _(i) is maintained according to subclause2.3.5.1.1. or 2.3.5.1.2.

2.3.5.1.1. Type A1 Multi-Channel Access Procedure

The counter N as described in subclause 2.3.1. (i.e., the counter Nconsidered in a CAP) is independently determined for each channel c_(i)and is denoted as N_(c) _(i) .

In the case where the eNB/gNB ceases a transmission on any one channelc_(j)∈C, if the absence of any other technology sharing the channel maynot be guaranteed on a long term basis (e.g. by level of regulation),for each channel c_(i) (c_(i) is different from c_(j), c_(i)≠c_(j)), theeNB/gNB may resume decrementing N_(c) _(i) when idle sensing slots aredetected either after waiting for a duration of 4·T_(sl) or afterreinitializing N_(c) _(i) .

2.3.5.1.2. Type A2 Multi-Channel Access Procedure

For each channel c_(j)∈C, the counter N is determined as described insubclause 2.3.1. and denoted as N_(c) _(j) , where c_(j) is a channelthat has the largest CW_(p) value. For each channel c_(i), N_(c) _(i)=N_(c) _(j) .

When the eNB/gNB ceases a transmission on any one channel for whichN_(c) _(i) is determined, the eNB/gNB reinitializes N_(c) _(i) for allchannels.

2.3.5.2. Type B Multi-Channel Access Procedure

A channel c_(j)∈C may be selected by the eNB/gNB as follows.

-   -   The eNB/gNB selects c_(j) by uniformly randomly choosing c_(j)        from C before each transmission on multiple channels c_(j)∈C, or    -   the eNB/gNB selects c_(j) no more frequently than once every 1        second.

Herein, C is a set of channels on which the eNB/gNB intends to transmit,and i=0, 1, . . . q−1 where q is the number of channels on which theeNB/gNB intends to transmit.

To transmit on a channel c_(j), the eNB/gNB performs channel access onthe channel c_(j) according to the procedure described in subclause2.2.1. with the modifications described in subclause 2.3.5.2.1. or2.3.5.2.2.

To transmit on a channel c_(i)≠c_(j) among channels c_(i)∈C,

-   -   for each channel c_(i), the eNB/gNB senses the channel c_(i) for        at least a sensing interval T_(mc)=25 us immediately before the        transmission on the channel c_(j). The eNB/gNB may perform a        transmission on the channel c_(i) immediately after sensing the        channel c_(i) to be idle for at least a sensing duration T_(mc).        The channel c_(i) may be considered to be idle for T_(mc) if the        channel is sensed to be idle during all the time durations in        which such idle sensing is performed on the channel c_(j) in the        given duration T_(mc).

The eNB/gNB does not perform a transmission on a channel c_(i)≠c_(j)(where c_(i)∈C), for a period exceeding T_(mcot,p) as given in Table 12,where the value of T_(mcot,p) is determined using the channel accessparameters used for the channel c_(j).

For the procedure in this subclause, the channel frequencies of the setC of channels selected by the gNB is a subset of one of predefined setsof channel frequencies.

2.3.5.2.1. Type B1 Multi-Channel Access Procedure

A single CW_(p) value is maintained for a set of channels C.

For determining CW_(p) for channel access on a channel c_(j), step 2 ofthe procedure described in subclause 2.3.3. is modified as follows.

-   -   If at least Z=80% of HARQ-ACK values corresponding to PDSCH        transmission(s) in reference subframe k of all channels c_(i)∈C        are determined as NACK, increase CW_(p) for each priority class        p∈{1, 2, 3, 4} to the next higher allowed value; otherwise, go        to step 1.

For determining CW_(p) for a set of channels C, any PDSCH that fully orpartially overlaps with any channel c_(i)∈C may be used in the proceduredescribed in subclause 2.3.3.2.

2.3.5.2.2. Type B2 Multi-Channel Access Procedure

A value CW_(p) is maintained independently for each channel c_(i)∈Cusing the procedure described in subclause 2.3.3. For determining CW_(p)for a channel c_(i), any PDSCH that fully or partially overlaps with thechannel c_(i) may be used in the procedure described in subclause2.3.3.2. For determining N_(init) for the channel c_(j), the CW_(p)value of a channel c_(j1)∈C is used, where c_(j1) is the channel with alargest CW_(p) among all channels in the set C.

2.4. Uplink Channel Access Procedures

A UE and a BS scheduling or configuring UL transmission(s) for the UEperform the following procedures for the UE to access channel(s) (onwhich LAA SCell transmission(s) are performed). On the assumption of aPCell being a licensed band and one or more SCells being an unlicensedband are basically configured for the UE and the BS, the followingdescription is given of a UL CAP to which various embodiments of thepresent disclosure are applied However, the UL CAP may also be appliedin the same manner, when only an unlicensed band is configured for theUE and the BS.

2.4.1. Channel Access Procedures for Uplink Transmission(s)

The UE may access a channel on which UL transmission(s) are performedaccording to one of the Type 1 or Type 2. UL CAP. The Type 1 CAP isdescribed in subclause 2.3.1.1. The Type 2 CAP is described in subclause2.3.1.2.

If a UL grant scheduling a PUSCH transmission indicates the Type 1 CAP,the UE performs the Type 1 CAP for performing transmissions including aPUSCH transmission, unless stated otherwise in this subclause.

If a UL grant scheduling a PUSCH transmission indicates the Type 2 CAP,the UE performs the Type 2 CAP for performing transmissions including aPUSCH transmission, unless stated otherwise in this subclause.

The UE performs the Type 1 CAP for performing a transmission includingan autonomous PUSCH transmission in configured UL resources, unlessstated otherwise in this subclause.

The UE performs the Type 1 CAP for performing SRS transmissions notincluding a PUSCH transmission. A UL channel access priority class p=1is used for SRS transmissions not including a PUSCH.

TABLE 18 Channel Access Priority allowed Class (p) m_(p) CW_(min, p)CW_(max, p) T_(ulmcot, p) CW_(p) sizes 1 2 3 7 2 ms {3, 7} 2 2 7 15 4 ms{7, 15} 3 3 15 1023 6 ms or 10 ms {15, 31, 63, 127, 255, 511, 1023} 4 715 1023 6 ms or 10 ms {15, 31, 63, 127, 255, 511, 1023} NOTE1: For p =3, 4, T_(ulmcot, p) = 10 ms if the higher layer parameterabsenceOfAnyOtherTechnology-r14 or absenceOfAnyOtherTechnology-r16 isprovided, otherwise, T_(ulmcot, p) = 6 ms. NOTE 2: When T_(ulmcot, p) =6 ms it may be increased to 8 ms by inserting one or more gaps. Theminimum duration of a gap shall be 100 us. The maximum duration beforeincluding any such gap shall be 6 ms.

2.4.1.1. Channel Access Procedures and UL-Related Signaling

If a UE detects a ‘UL configuration for LAA’ field and/or a ‘UL durationand offset’ field (e.g., in DCI format 1C), the following is applicable.

-   -   If the ‘UL configuration for LAA’ field and/or the ‘UL duration        and offset’ field configures and/or indicates ‘UL offset’ 1 and        ‘UE duration’ d for subframe n, then the UE may use the Type 2        CAP for transmissions in subframe n+l+i (where i=0, 1, . . .        d−1), irrespective of a channel access type signaled in a UL        grant for those subframes, if the end of a UE transmission        occurs in or before subframe n+l+d−1.    -   If the ‘UL configuration for LAA’ field and/or the ‘UL duration        and offset’ field configures and/or indicates ‘UL offset’ 1 and        an ‘UL duration’ d for subframe n and a ‘COT sharing indication        for AUL’ field is set to ‘1’, then a UE configured with        autonomous UL may use the Type 2 CAP for autonomous UL        transmission(s), assuming any priority class in subframes (where        i=0, 1, . . . d−1), if the end of the UE autonomous UL        transmission occurs in or before subframe n+l+d−1 and the        autonomous UL transmissions between n+l and n+l+d−1 are        contiguous.    -   If the ‘UL configuration for LAA’ field and/or the ‘UL duration        and offset’ field indicates ‘UL offset’ 1 and an ‘UL duration’ d        for subframe n and the ‘COT sharing indication for AUL’ field is        set to ‘0’, then a UE configured with autonomous UL should not        transmit autonomous UL in subframe n+l+i (where i=0, 1, . . .        d−1).

2.4.1.2. Channel Access Procedures for Consecutive UL Transmission(s)

For contiguous UL transmission(s), the following is applicable.

-   -   If a UE is scheduled to perform a set of UL transmission(s)        including a PUSCH using a UL grant, and if the UE may not access        the channel for a transmission in the set prior to the last        transmission, the UE should attempt to transmit a next        transmission according to a channel access type indicated by the        UL grant.    -   If the UE is scheduled to perform a set of consecutive UL        transmissions without gaps including a PUSCH using one or more        UL grants, and if the LTE transmits one of the scheduled UL        transmissions in the set after accessing the channel according        to one of the Type 1 or Type 2 UL CAP, the UE may continue        transmission of the remaining UL transmissions in the set, if        any.    -   The UE does not expect different channel access types to be        indicated for any consecutive UL transmissions without gaps        between the transmissions.

For contiguous UL transmissions(s) including a transmission pause, thefollowing is applicable.

-   -   If a UE is scheduled to perform a set of consecutive UL        transmissions without gaps using one or more UL grants, if the        UE has stopped transmitting during or before one of these UL        transmissions in the set and prior to the last UL transmission        in the set, and if the channel is sensed by the UE to be        continuously idle after the UE has stopped transmitting, the UE        may transmit a later UL transmission in the set using the Type 2        CAP.    -   If a channel sensed by the UE is not continuously idle after the        UE has stopped transmitting, the UE may perform a later UL        transmission in the set using the Type 1 CAP with a UL channel        access priority class indicated in the DCI corresponding to the        UL transmission.

2.4.1.3. Conditions for Maintaining Type 1 UL Channel Access Procedures

If a UE receives DCI indicating a UL grant scheduling a PUSCHtransmission using the Type 1 CAP and/or DCI indicating a DL grantscheduling a PUCCH transmission using the Type 1 CAP, and if the UE hasan ongoing Type 1 CAP before the PUSCH or PUCCH transmission startingtime,

-   -   if the UL channel access priority class value p₁ used for the        ongoing Type 1 CAP is equal to or larger than a UL channel        access priority class value p₂ indicated by the DCI, the UE may        perform the PUSCH transmission in response to the UL grant by        accessing the channel by using the ongoing Type 1 CAP.    -   If the UL channel access priority class value p₁ used for the        ongoing Type 1 CAP is less than the UL channel access priority        class value p₂ indicated by the DCI, the UE terminates the        ongoing CAP.    -   The UE may perform a PUCCH transmission in response to the DL        grant by accessing the channel by using the ongoing Type 1 CAP.

2.4.1.4. Conditions for Indicating Type 2 Channel Access Procedures

If the BS has transmitted on the channel according to the CAP describedin subclause 2.3.1, the BS may indicate the Type 2 CAP in DCI of a ULgrant which schedules a transmission including a PUSCH on a channel insubframe n.

Alternatively, when the BS has transmitted on the channel according tothe CAP described in subclause 2.3.1, the BS may indicate, the BS mayindicate, using the ‘UL Configuration for LAA’ field and/or the ‘ULduration and offset’ field, that the UE may perform the Type 2 CAP fortransmissions including a PUSCH on a channel in subframe n.

Alternatively, if the UL transmission occurs within a time intervalstarting at t₀ and ending at t₀+T_(CO), the BS may schedule a ULtransmission on a channel, which follows a transmission by the BS onthat channel with the Type 2A CAP for the UL transmission. Herein,T_(CO)=T_(m cot,p)+T_(g) and each parameter may be defined as follows.

-   -   t₀: a time instant when the BS has started a transmission.    -   T_(mcot,p): a value determined by the BS as described in        subclause 2.2.    -   T_(g): the total duration of all gaps of a duration greater than        25 us that occur between the DL transmission of the BS and a UL        transmission scheduled by the BS, and between any two UL        transmissions scheduled by the BS, starting from t₀.

If the UL transmissions may be scheduled contiguously, the BS schedulesthe UL transmissions without gaps between the consecutive ULtransmissions within t₀ and t₀+T_(CO).

For a UL transmission on the channel following a transmission of the BSon the channel within a duration T_(short_ul)=25 us, the UE may performthe Type 2A CAP for the UL transmission.

If the BS indicates the Type 2 CAP for the UE by the DCI, the BSindicates the channel access priority class used to obtain access to thechannel by the DCI.

2.4.1.5. Channel Access Procedure for UL Multi-Channel Transmission(s)

If a UE

-   -   is scheduled to transmit on a set of channels C, if the Type 1        CAP is indicated by UL scheduling grants for UL transmissions on        the set of channels C, and if the UL transmissions are scheduled        to start at the same time on all channels in the set of channels        C, and/or    -   intends to perform a UL transmission on configured resources on        the set of channels C with the Type 1 CAP, and

if the channel frequencies of the set of channels C is a subset of oneof the sets of preconfigured channel frequencies,

-   -   the UE may transmit on a channel c_(i)∈C using the Type 2 CAP.        -   If the Type 2 CAP is performed on the channel c_(i)            immediately before the UE transmission on the channel            c_(j)∈C (where i≠j), and    -   if the UE has accessed a channel c_(j) using the Type 1 CAP,        -   the channel c_(j) is selected by the UE uniformly randomly            from the set of channels C before performing the Type 1 CAP            on any channel in the set of channels C.    -   If the UE fails to access any of the channels, the UE may not        transmit on the channel c_(i)∈C within the bandwidth of a        carrier of a carrier bandwidth, on which the UE is scheduled or        configured by UL resources.

2.4.2. Type 1 UL Channel Access Procedure

This subclause describes a CAP performed by a UE, in which a timeduration spanned by sensing slots that are sensed to be idle before a ULtransmission(s) is random. The subclause is applicable to the followingtransmissions.

-   -   PUSCH/SRS transmission(s) scheduled or configured by the BS.    -   PUCCH transmission(s) scheduled or configured by the BS.    -   Transmission(s) related to a random access procedure (RAP).

The UE may perform a transmission using the Type 1 CAP after a channelis sensed to be idle during the slot durations of a defer durationT_(d), and a counter N is zero in step 4. The counter N is adjusted bysensing the channel for additional slot duration(s) according to thefollowing procedure.

1) Set N=N_(init) where N_(init) is a random number uniformlydistributed between 0 and CW_(p), and go to step 4.

2) If N>0 and the UE chooses to decrement the counter, set N=N−1.

3) Sense the channel for an additional slot duration, and if theadditional slot duration is idle, go to step 4; else, go to step 5.

4) If N=0, stop; else, go to step 2.

5) Sense the channel until either a busy slot is detected within anadditional defer duration T_(d) or all the slots of the additional deferduration T_(d) are detected to be idle.

6) If the channel is sensed to be idle during all the slot durations ofthe additional defer duration T_(d), go to step 4; else, go to step 5.

FIG. 21 is a diagram illustrating a UL CAP for transmission in anunlicensed band to which various embodiments of the present disclosureare applicable.

The afore-described Type 1 UL CAP of a UE may be summarized as follows.

For a UL transmission, a transmission node (e.g., a UE) may initiate aCAP to operate in an unlicensed band (2110).

The UE may select a backoff counter N randomly within a CW according tostep 1. N is set to an initial value N_(init) (2120). N_(init) is avalue randomly selected between 0 and CW_(p).

Subsequently, when the backoff counter value N is 0 according to step 4(2130; Y), the UE ends the CAP (2132). The UE may then transmit a Txburst (2134). On the other hand, if the backoff counter value is not 0(2130; N), the UE decrements the backoff counter value by 1 according tostep 2 (2140).

Subsequently, the UE checks whether a channel is idle (2150). If thechannel is idle (2150; Y), the UE checks whether the backoff countervalue is 0 (2130).

On the contrary, if the channel is not idle, that is, the channel isbusy (2150; N), the UE checks whether the channel is idle for a deferduration T_(d) (of 25 usec or more) longer than a slot duration (e.g., 9usec) according to step 5 (2160). If the channel is idle for the deferduration (2170; Y), the UE may resume the CAP.

For example, if the backoff counter value N_(init) is 10 and the channelis determined to be idle after the backoff counter value is decrementedto 5, the UE senses the channel for the defer duration and determineswhether the channel is idle. If the channel is idle for the deferduration, the UE may perform the CAP again from the backoff countervalue 5 (or the backoff counter value 4 after decrementing the backoffcounter value by 1), instead of setting the backoff counter valueN_(init).

On the other hand, if the channel is busy for the defer duration (2170;N), the UE checks again whether the channel is idle for a new deferduration by performing operation 2160 again.

If the UE has not performed a UL transmission on a channel on which ULtransmission(s) are performed after step 4 in the above procedure, theUE may perform a UL transmission on the channel, if the followingcondition is satisfied:

-   -   if the channel is sensed to be idle at least in a sensing slot        duration T_(sl) when the UE is ready to perform the        transmission; and    -   if the channel has been sensed to be idle during all the slot        durations of a defer duration T_(d) immediately before the        transmission.

On the contrary, if the channel has not been sensed to be idle in asensing slot duration T_(sl) when the UE first senses the channel afterit is ready to transmit, or if the channel has not been sensed to beidle during any of the sensing slot durations of a defer duration T_(d)immediately before the intended transmission, the UE proceeds to step 1after sensing the channel to be idle during the slot durations of thedefer duration T_(d).

The defer duration T_(d) includes a duration T_(f)(=16 us) immediatelyfollowed by m_(p) consecutive slot durations where each slot durationT_(sl) is 9 us, and T_(f) includes an idle slot duration T_(sl) at thestart of T_(f).

CW_(min,p)≤CW_(p)≤CW_(max,p) is the contention window. CW_(p) adjustmentis described in subclause 2.3.2.

CW_(min , p)  and  CW_(max , p)are chosen before step 1 of the above procedure.

m_(p), CW_(min , p)  and  CW_(max , p)are based on a channel access priority class signaled to the UE (seeTable 18).

X_(Thresh) is adjusted according to subclause 2.3.3. as described below.

2.4.3. Type 2 UL Channel Access Procedure

This subclause describes a CAP performed by a UE, in which a timeduration spanned by sensing slots sensed to be idle before a ULtransmission(s) is deterministic.

If the UE is indicated by the BS to perform the Type 2 UL CAP, the UEfollows the procedure described in subclause 2.4.3.1.

2.4.3.1. Type 2A UL Channel Access Procedure

If the UE is indicated to perform the Type 2A UL CAP, the UE uses theType 2A UL CAP for a UL transmission. The UE may perform thetransmission immediately after sensing the channel to be idle for atleast a sensing duration T_(short_ul)=25 us. T_(short_ul) includes aduration T_(f)=16 us immediately followed by one slot sensing slotduration T_(sl)=9 us, and T_(f) includes a sensing slot at the start ofT_(f). The channel is considered to be idle for T_(short_ul), if bothsensing slots of T_(short_ul) are sensed to be idle.

2.4.3.2. Type 2B UL Channel Access Procedure

If the UE is indicated to perform a Type 2B UL CAP, the UE uses the Type2B UL CAP for a UL transmission. The UE may perform the transmissionimmediately after sensing the channel to be idle within a duration ofT_(f)=16 us. T_(f) includes a sensing slot that occurs within the last 9us of T_(f). The channel is considered to be idle within the durationT_(f), if the channel is sensed to be idle for a total of at least 5 uswith at least of 4 us sensing occurring in the sensing slot.

2.4.3.3. Type 2C UL Channel Access Procedure

If the UE is indicated to perform a Type 2C UL CAP for a ULtransmission, the UE does not sense the channel before the transmission.The duration of the corresponding UL transmission is at most 584 us.

2.4.4. Contention Window Adjustment Procedure

If the UE performs a transmission associated with a channel accesspriority class p on a channel, the UE maintains the contention windowvalue CW_(p) and adjusts CW_(p) for the transmission before step 1 ofthe procedure described in subclause 2.4.2. (i.e., before a CAP isperformed).

2.4.4.1. Contention Window Adjustment Procedure for UL TransmissionScheduled/Configured by eNB

If the UE performs a transmission using the Type 1 CAP associated with achannel access priority class p on a channel, the UE maintains thecontention window value CW_(p) and adjusts CW_(p) for the transmissionbefore step 1 of the procedure described in subclause 2.4.1. (i.e.,before the CAP is performed), using the following procedure.

-   -   If the UE receives a UL grant and/or an autonomous uplink        downlink feedback information (AUL-DFI), the contention window        size for all the priority classes is adjusted as follows.        -   If a new data indicator (NDI) value for at least one HARQ            process associated with HARQ_ID_ref is toggled, and/or if            the HARQ-ACK value(s) for at least one of the HARQ processes            associated with HARQ_ID_ref received in the earliest AUL-DFI            after n_(ref)+3 indicates ACK,            -   for every priority class p∈{1, 2, 3, 4}, set                CW_(p)=CW_(min,p).        -   Otherwise, increase CW_(p) for every priority class p∈{1, 2,            3, 4} to the next higher allowed value.

Herein, HARQ_ID_ref is the HARQ process ID of a UL-SCH in referencesubframe n_(ref). The reference subframe n_(ref) is determined asfollows.

-   -   If the UE receives a UL grant in subframe n_(g), subframe n_(w)        is the most recent subframe before subframe n_(g)−3 in which the        UE has transmitted a UL-SCH using the Type 1 CAP.        -   If the UE performs transmissions including a UL-SCH without            gaps starting with subframe n₀ and in subframes n₀, n₁, . .            . , n_(w), reference subframe n_(ref) is subframe n₀.        -   Otherwise, reference subframe n_(ref) is subframe n_(w).

If the UE is scheduled to perform transmissions without gaps including aPUSCH in a set of subframes n₀, n₁, . . . , n_(w-1) using the Type 1CAP, and if the UE is not able to perform any transmission including aPUSCH in the set of subframes, the UE may keep the value CW_(p)unchanged for every priority class p∈{1, 2, 3, 4}.

If the reference subframe for the last scheduled transmission is alson_(ref), the UE may keep the value CW_(p) for every priority class p∈{1,2, 3, 4} the same as that for the last scheduled transmission includinga PUSCH using the Type 1 CAP.

If

CW_(p) = CW_(max , p),the next higher allowed value for adjusting CW_(p) is CW_(max,p).

If

CW_(p) = CW_(max , p)is consecutively used K times for generation of N_(init), CW_(p) isreset to CW_(min,p) only for that priority class p for which

CW_(p) = CW_(max , p)is consecutively used K times for generation of N_(init). K is selectedby the UE from the set of values {1, 2, . . . , 8} for each priorityclass p∈{1, 2, 3, 4}.

2.4.4.2. Contention Window Adjustment Procedures for UL TransmissionsScheduled/Configured by gNB

If the UE performs transmissions using the Type 1 CAP associated with achannel access priority class p on a channel, the UE maintains thecontention window value CW_(p) and adjusts CW_(p) for thosetransmissions before step 1 of the procedure described in subclause2.4.1. (i.e., before the CAP is performed), using the following steps.

1> For every priority class p∈{1,2,3,4}, set CW_(p)=CW_(min, p).

2> If an HARQ-ACK feedback is available after the last update of CW_(p),go to step 3. Otherwise, if the UE transmission after the proceduredescribed in subclause 2.4.1. does not include a retransmission or isperformed within a duration T_(w) from the end of a reference durationcorresponding to the earliest UL transmission burst after the lastupdate of CW_(p) transmitted after the procedure described in subclause2.4.1., go to step 5; otherwise go to step 4.

3> The HARQ-ACK feedback(s) corresponding to PUSCH(s) in the referenceduration for the latest UL transmission burst for which an HARQ-ACKfeedback is available is used as follows.

a. If at least one HARQ-ACK feedback is ‘ACK’ for PUSCH(s) with TB-basedtransmissions or at least 10% of HARQ-ACK feedbacks is ‘ACK’ forPUSCH(s) with CBG-based transmissions, go to step 1; otherwise go tostep 4.

4> Increase CW_(p) for every priority class p∈{1, 2, 3, 4} to the nexthigher allowed value.

5> For every priority class p∈{1, 2, 3, 4}, maintain CW_(p) as it is; goto step 2.

The HARQ-ACK feedback, reference duration and duration Tw in the aboveprocedure are defined as follows.

-   -   HARQ-ACK feedback for PUSCH(s) transmissions is expected to be        provided to UE(s) explicitly or implicitly where implicit        HARQ-ACK feedback for the purpose of contention window        adjustment in this subclause is determined based on an        indication for a new transmission or retransmission in DCI        scheduling PUSCH(s) as follows.        -   a new transmission is indicated, ‘ACK’ is assumed for the            TBs or CBGs in the corresponding PUSCH(s) for the TB-based            and CBG-based transmission, respectively.        -   If a retransmission is indicated for TB-based transmissions,            ‘NACK’ is assumed for the TBs in the corresponding PUSCH(s).        -   If a retransmission is indicated for CBG-based            transmissions, and if a bit value in a code block group            transmission information (CBGTI) field is ‘0’ or ‘1’, ‘ACK’            or ‘NACK’ is assumed for the corresponding CBG in the            corresponding PUSCH(s), respectively.    -   The reference duration corresponding to a channel occupancy        initiated by the UE, including transmission of PUSCH(s) is        defined in this subclause as a duration starting from the        beginning of the channel occupancy until the end of the first        slot where at least one unicast PUSCH is transmitted over all        the resources allocated for the PDSCH, or until the end of the        first transmission burst by the gNB that contains unicast        PUSCH(s) transmitted over all the resources allocated for the        PDSCH, whichever occurs earlier. If the channel occupancy        includes a unicast PUSCH, but it does not include any unicast        PUSCH transmitted over all the resources allocated for that        PUSCH, then, the duration of the first transmission burst by the        UE within the channel occupancy that contains PUSCH(s) is the        reference duration for CWS adjustment.    -   T_(w)=max(T_(A), T_(B)+1 ms) where T_(B) is the duration in ms        of a transmission burst from the start of the reference        duration. If the absence of any other technology sharing the        channel may not be guaranteed on a long-term basis (e.g. by        level of regulation), T_(A)=5 ms, and otherwise, T_(A)=10 ms.

If the UE performs transmissions using the Type 1 CAP associated with achannel access priority class p on a channel and the transmissions arenot associated with explicit or implicit HARQ-ACK feedbacks as describedabove in this subclause, the UE adjusts CW_(p) before step 1 in theprocedure described in subclause 2.4.1., using the latest CW_(p) usedfor any UL transmissions on the channel using the Type 1 CAP associatedwith the channel access priority class p. If the corresponding channelaccess priority class p has not been used for any UL transmission on thechannel, CW_(p)=CW_(min,p) is used.

2.4.4.3. Common Procedures for CWS Adjustments for UL Transmissions

The following applies to the procedures described in subclauses 2.4.4.1and 2.4.4.2.

-   -   If

CW_(p) = CW_(max , p)the next higher allowed value for adjusting CW_(p) is CW_(max, p).

-   -   If

$\begin{matrix}{{CW}_{p} = {CW}_{\max,p}} & \;\end{matrix}$is consecutively used K times for generation of N_(init), CW_(p) isreset to CW_(min) only for that priority class p for which

CW_(p) = CW_(max , p)is consecutively used K times for generation of N_(init). K is selectedby the UE from the set of values {1, 2, . . . , 8} for each priorityclass p∈{1, 2, 3, 4}.

2.4.5. Energy Detection Threshold Adaptation Procedure

A UE accessing a channel on which UL transmission(s) are performedshould set an energy detection threshold X_(Thres) to be less than orequal to a maximum energy detection threshold X_(Thresh_max).

The maximum energy detection threshold X_(Thresh_max) is determined asfollows.

-   -   If the UE is configured with a higher layer parameter        maxEnergyDetectionThreshold-r14 and/or        maxEnergyDetectionThreshold-r16,        -   X_(Thresh_max) is set to be equal to a value signaled by the            higher-layer parameter.    -   Otherwise,        -   the UE should determine X′_(Thresh_max) according to the            procedure described in subclause 2.3.3.1.        -   If the UE is configured with a higher layer parameter            energyDetectionThresholdOffset-r14 and/or            energyDetectionThresholdOffset-r16,            -   X′_(Thresh_max) is set by adjusting X_(Thresh_max)                according to an offset value signaled by the                higher-layer parameter.        -   Otherwise,            -   the UE sets X_(Thresh_max)=X′_(Thresh_max).

2.3.3.1. Default Maximum Energy Detection Threshold ComputationProcedure

If the higher-layer parameter ‘absenceOfAnyOtherTechnology-r14’ and/or‘absenceOfAnyOtherTechnology-r16’ is provided:

$X_{{Thresh}\_\max}^{\prime} = {\min\begin{Bmatrix}{{T_{\max} + {10\; d\; B}},} \\X_{r}\end{Bmatrix}}$

-   -   where X_(r) is a maximum energy detection threshold defined in        dBm by regulatory requirements when such requirements are        defined. Otherwise X_(r)=T_(max)+10 dB

Otherwise:

$X_{{Thres}\_\max}^{\prime} = {\max\begin{Bmatrix}{{{- 72} + {{10 \cdot \log}\; 10\left( {{BW}\;{{MHz}/20}\mspace{11mu}{MHz}} \right){dBM}}},} \\{\min\begin{Bmatrix}{T_{\max},} \\\begin{matrix}{T_{\max} - T_{A} +} \\\left( {P_{H} + {{10 \cdot \log}\; 10\left( {{BW}\mspace{11mu}{{MHz}/20}\mspace{11mu}{MHz}} \right)} - P_{TX}} \right)\end{matrix}\end{Bmatrix}}\end{Bmatrix}}$

where

-   -   T_(A)=10 dB    -   P_(H)=23 dBm;    -   P_(TX) is the set to the value of P_(CMAX_H,c)    -   T_(max)(dBm)=10·log 10(3.16228·10⁻⁸ (mW/MHz)·BWMHz (MHz))        -   BWMHz is the single channel bandwidth in MHz.

3. Various Embodiments of the Present Disclosure

A detailed description will be given of various embodiments of thepresent disclosure based on the above technical ideas. Theafore-described contents of clause 1 and clause 2 are applicable tovarious embodiments of the present disclosure described below. Forexample, operations, functions, terminologies, and so on which are notdefined in various embodiments of the present disclosure may beperformed and described based on clause 1 and clause 2.

Symbols/abbreviations/terms used in the description of variousembodiments of the present disclosure may be defined as follows.

-   -   PDCCH: physical downlink control channel    -   PDSCH: physical downlink shared channel    -   PUSCH: physical uplink shared channel    -   CSI: channel state information    -   RRM: radio resource management    -   DCI: downlink control information    -   CAP: channel access procedure    -   Ucell: unlicensed cell    -   TBS: transport block size    -   SLIV: starting and length indicator value (a field indicating        the index of the starting symbol and the number of symbols in a        slot of a PDSCH and/or a PUSCH. This field may be carried on a        PDCCH scheduling the PDSCH and/or the PUSCH.)    -   BWP: bandwidth part (it may include contiguous RBs on the        frequency axis and correspond to one numerology (e.g., an SCS, a        CP length, a slot/mini-slot duration, or the like). Although        multiple BWPs may be configured in one carrier (e.g., the number        of BWPs per carrier may also be limited), the number of active        BWPs may be limited to a value less than the number (e.g., 1) of        the multiple BWPs in the carrier.    -   CORESET: control resource set (a time and frequency resource        area in which a PDCCH may be transmitted. The number of CORESETs        per BWP may be limited.)    -   REG: resource element group    -   SFI: slot format indicator (an indicator indicating a        symbol-level DL/UL direction in specific slot(s), which may be        transmitted on a GC-PDCCH.)    -   COT: channel occupancy time    -   CO structure: channel occupancy structure. This may be related        to one or more of time-domain resources and/or frequency-domain        resources occupied by a transmission on a channel by a BS/UE        after a CAP is performed. The term CO structure may be        interchangeably used with COT structure in an equivalent        meaning.    -   SPS: semi-persistent scheduling

As more and more communication devices require larger communicationcapacities, efficient use of a limited frequency band becomes asignificant requirement. In this context, techniques of using anunlicensed band such as 2.4 GHz mainly used in the legacy WiFi system or5 GHz and/or 60 GHz which has newly attracted attention are underconsideration for a cellular communication system such as 3GPP LTE/NR.Hereinbelow, the term unlicensed band may be replaced with unlicensedspectrum or shared spectrum.

To transmit a signal in an unlicensed band, a UE or a BS uses wirelesstransmission and reception based on contention between communicationnodes. That is, when each communication node is to transmit a signal inthe unlicensed band, the communication node may confirm that anothercommunication node is not transmitting a signal in the unlicensed bandby performing channel sensing before the signal transmission. For theconvenience of description, this operation is defined as a listen beforetalk (LBT) operation or a CAP. Particularly, the operation of checkingwhether another communication node is transmitting a signal is definedas carrier sensing (CS), and determining that another communication nodeis not transmitting a signal is defined as confirming clear channelassessment (CCA).

In an LTE/NR system to which various embodiments of the presentdisclosure are applicable, an eNB/gNB or a UE may also have to performan LBT operation or a CAP for signal transmission in an unlicensed band.In other words, the eNB/gNB or the UE may transmit a signal in theunlicensed band, using or based on the CAP.

Further, when the eNB/gNB or the UE transmits a signal in the unlicensedband, other communication nodes such as WiFi nodes should not interferewith the eNB/gNB or the UE by performing a CAP. For example, the WiFistandard (e.g., 801.11ac) specifies a CCA threshold as −62 dBm for anon-WiFi signal and as −82 dBm for a WiFi signal. Accordingly, a station(STA) or access point (AP) operating in conformance to the WiFi standardmay not transmit a signal to prevent interference, for example, whenreceiving a signal other than a WiFi signal at or above −62 dBm.

In the following description of various embodiments of the presentdisclosure, when it is said that a BS succeeds in a CAP, this may implythat the BS determines that an unlicensed band is idle and thus startsto transmit a signal in the unlicensed band at a specific time. On thecontrary, when it is said that the BS fails in the CAP, this may implythat the BS determines that the unlicensed band is busy and thus doesnot start to transmit a signal in the unlicensed band at a specifictime.

For co-existence with a WiFi system in which a CAP is performed in unitsof 20 MHz, a carrier bandwidth is basically limited to 20 MHz in an LTELAA system. However, the carrier bandwidth may vary according to SCSs inthe NR system. Thus, the carrier bandwidth may be larger than 20 MHz.Further, the UE may be configured with a BWP narrower than the carrierbandwidth operated by the gNB. The same thing may be applied to anNR-unlicensed band (NR-U) system. In consideration of a frequency unitin which the CAP is performed in the WiFi system, the carrier bandwidthmay be set to a multiple of 20 MHz in the NR-U system.

Accordingly, 20 MHz has a meaning as a frequency unit in which the CAPis performed, and it will be clearly understood to those skilled in theart that various embodiments of the present disclosure are not limitedto the specific frequency value of 20 MHz.

Meanwhile, the above-described carrier bandwidth may be understood as awideband, and a frequency unit in which the CAP is performed may beunderstood as a CAP subband and/or a CAP (LBT) bandwidth and/or achannel. The CAP subband and/or LBT bandwidth and/or channel is acarrier including a set of contiguous RBs in which the CAP is performedwithin an unlicensed band (and/or a shared spectrum) or a part of thecarrier.

When consecutive transmissions without a gap on the time axis or a setof transmissions without a gap greater than a predetermined size (e.g.,16 us) on the time axis from one transmission node (a gNB and/or a UE)is referred to as a burst or a Tx burst) in an unlicensed-band NRsystem, various embodiments of the present disclosure described belowmay be related to methods of transmitting and receiving an initialsignal to indicate a burst transmission and enable the bursttransmission to be recognized, a PDCCH monitoring method, and across-carrier scheduling (CCS) method.

In the NR system, for example, a scheduling unit is a slot and atime-domain structure which also allows only a part of a slot to befilled for transmission (mini-slot transmission) may be supported. Forexample, this may be a time-domain structure considered to support anunlicensed band.

Accordingly, considering the time-domain structure of the NR system,while the following description is given of various embodiments of thepresent disclosure, focusing on operations in an unlicensed band (and anNR system operating in the unlicensed band), those skilled in the artwill understand that various embodiments of the present disclosure arealso readily applicable to a licensed band (and an NR system operatingin the licensed band).

Operations according to various embodiments of the present disclosurewill be described below in detail. Those skilled in the art willunderstand that the various embodiments of the present disclosuredescribed below may be combined in whole or in part to constitute othervarious embodiments of the present disclosure, unless contradicting witheach other.

3.1. Method of Transmitting and Receiving Initial Signal

FIG. 23 is a diagram illustrating an exemplary method of transmittingand receiving an initial signal according to various embodiments of thepresent disclosure.

Referring to FIG. 23 , in operation 2301 according to an exemplaryembodiment of the present disclosure, a BS may perform a DL CAP for anunlicensed band to transmit a DL signal to a UE. For example, the DL CAPmay be one or more of the afore-described various DL CAPs for DLtransmission.

In operation 2303 according to an exemplary embodiment of the presentdisclosure, when the BS determines that the unlicensed band is available(or a channel configured in the unlicensed band is idle) by the DL CAP,the BS may transmit an initial signal and/or a DL signal in theunlicensed band (or on the channel configured in the unlicensed band) tothe UE based on a method according to various embodiments of the presentdisclosure.

Accordingly, for example, the UE may expect the BS to transmit the DLsignal based on the initial signal received earlier than the DL signal.Thus, the UE may receive the DL signal from the BS.

For example, the UE may transmit or receive a signal associated with thereceived DL signal to or from the BS. For example, when the UE is totransmit a specific signal to the BS, the UE may transmit the specificsignal to the BS based on the result of a UL CAP. For example, the ULCAP may be one or more of the afore-described various UL CAPs for ULtransmission.

In the descriptions of this subclause and various embodiments of thepresent disclosure, determination of the inside/outside of a COT mayrefer to acquisition/transmission of a DL burst based on a DL signaland/or a PDCCH as in [Method #1-1A], [Method #1-2A], [Method #1-1B], and[Method #1-2B] described below.

Information elements (IEs) described in this subclause and variousembodiments of the present disclosure may be defined as follows.

For example, precoderGranularity is an IE included in an RRC parameterControlResourceSet used to configure a time and/or frequency CORESET forDCI detection. For example, this IE may provide information about aprecoder granularity on the frequency axis.

For example, precoderGranularity may be set to one of sameASREG-bundleand allContiguousRBs (ENUMERATED {sameAsREG-bundle, allContiguousRBs}).

For example, sameAsREG-bundle may be information indicating that afrequency-domain precoder granularity for each CORESET is equal to afrequency-domain REG bundle size.

For example, allContiguousRBs may be information indicating that afrequency-domain precoder granularity for each CORESET is equal to thenumber of frequency-domain contiguous RBs in the CORESET.

For example, pdcch-DMRS-ScramblingID is an IE included in the RRCparameter ControlResourceSet used to configure a time and/or frequencyCORESET for DCI detection. pdcch-DMRS-ScramblingID may be an RRCparameter for PDCCH DMRS scrambling initialization.

For example, searchSpaceType may be an IE included in an RRC parameterSearchSpace defining how and/or where a PDCCH (PDCCH candidates) is tobe detected, and each search space may be associated with oneControlResourceSet.

For example, searchSpaceType may be an RRC parameter indicating a CSSand/or a USS and/or a DCI format for monitoring.

For example, frequencyDomainResources may be an IE included in the RRCparameter ControlResourceSet.

For example, frequencyDomainResources may provide information about thefrequency-domain resources of the CORESET.

Now, a description will be given of a specific operation of a UE and/ora BS based on an initial signal transmission and reception methodaccording to various embodiments of the present disclosure.

For example, when transmission data is generated or a signal/channelsuch as an RS for measurement requires periodic transmissions in alicensed channel/carrier at the BS, it may be guaranteed that thetransmission starts at an intended time.

On the other hand, even though the BS is to transmit a DL signal at aspecific time in an unlicensed channel/carrier, the BS may not start thetransmission when the BS fails in a CAP immediately before the specifictime. That is, the BS may or may not transmit a signal in the unlicensedchannel/carrier depending on whether the BS succeeds in the CAP.Therefore, the UE needs to identify when the BS starts a transmission,and thus requires a signal indicating whether a DL transmission isactually performed. This signal indicating whether a DL transmission isactually performed may be referred to as an initial signal.

For example, the initial signal may be transmitted at the start of a Txburst.

In another example, the initial signal may be transmitted in everyspecific time unit of the Tx burst (per specific time unit, for example,per slot boundary in the Tx burst).

According to various embodiments of the present disclosure, the initialsignal may be transmitted in the unlicensed channel/carrier at least forthe following purposes.

1> For example, to receive DCI in a Tx burst from a serving cell andreceive a PDSCH scheduled by the DCI.

2> For example, to perform CSI measurement in a CSI-RS transmitted in aTx burst from a serving cell.

3> For example, to perform RRM measurement in signals of a Tx burst froma serving cell/neighbor cell.

4> For example, for automatic gain control (AGC) gain setting: forexample, the initial signal may be used to set AGC for receiving a bursttransmitted after the initial signal.

5> For example, (coarse or fine) time and/or frequency synchronization:for example, the initial signal may be used for accurate time and/orfrequency synchronization between signals (for RRM or CSI measurement)to be transmitted periodically. Alternatively, for example, the initialsignal may be used to detect a frame/subframe/slot/symbol boundary.Alternatively, for example, an NR node may usually attempt todiscover/detect the initial signal without FFT, and only whendiscovering/detecting the initial signal, may perform FFT. In this case,there may be a gain in terms of battery saving.

6> For example, for power saving: for example, the UE does not performor performs minimally a DL reception operation such as PDCCH monitoringuntil before discovering/detecting the initial signal. Upon discovery ofthe initial signal, the UE is allowed to start the DL receptionoperation such as PDCCH monitoring. Therefore, power consumption of theUE may be reduced.

3.1.1. Operation on Receiver Side (Entity A)

3.1.1.1. [Method #1-1A] DL Tx Burst is Obtained Based on DL Signal

According to various embodiments of the present disclosure, specific DLsignal(s) may be defined as an initial signal. According to variousembodiments of the present disclosure, upon discovery of the initialsignal, the UE may recognize the presence of a DL Tx burst.Alternatively, according to various embodiments of the presentdisclosure, upon discovery of the specific DL signal(s), the UE mayrecognize the presence of a DL Tx burst.

For example, the specific DL signal(s) may be at least all or a part ofthe following signals.

-   -   PSS and/or SSS and/or PBCH DM-RS: In an exemplary embodiment, a        PSS and/or an SSS and/or a PBCH DM-RS defined in NR may be        modified and repeated along the time axis and/or may be extended        along the frequency axis. Thus, tracking performance may be        secured or transmission power may be increased.    -   PDCCH DM-RS: In an exemplary embodiment, the constraint that the        DM-RS includes only one symbol to minimize time-axis occupation        may be imposed.        -   In an exemplary embodiment, the DM-RS may be a separate            (PDCCH) DM-RS which is not linked to a specific CORESET. In            this case, for example, the DM-RS may be configured to            occupy a frequency band made up of a specific number of or            more RBs (e.g., 50 RBs) in consideration of the tracking            performance and/or transmission power of the DM-RS. For            example, a transmission periodicity (e.g., 7 symbols            (7-symbol periodicity)) may be additionally configured.        -   In an exemplary embodiment, the DM-RS may be a (PDCCH) DM-RS            linked to a specific CORESET. For example, in this case, the            DM-RS may be configured to occupy a frequency band made up            of a specific number of or more RBs (e.g., 50 RBs) in            consideration of the tracking performance and/or            transmission power of the DM-RS, and may be transmitted in a            specific REG or total REGs of the CORESET irrespective of a            PDCCH transmission. In another example, characteristically,            the DM-RS may be a DM-RS corresponding to a CORESET for            which precoderGranularity is set to allContiguousRBs. For            example, when precoderGranularity is set to allContiguousRBs            in the NR system, the UE may assume that the DM-RS exists in            every REG in contiguous RBs including REGs in mapped (or            discovered) PDCCH candidates. On the other hand, for            example, the UE may assume that the DM-RS exists in all REGs            (or some REG(s)) of the CORESET irrespective of the mapped            (or discovered) PDCCH candidates.        -   In an exemplary embodiment, the UE may be configured with a            specific PDCCH DM-RS as an initial signal by the BS. In            another example, when the UE is configured with a PDCCH            DM-RS associated with a CORESET satisfying a specific            condition, the UE may determine the PDCCH DM-RS as an            initial signal. For example, the CORESET satisfying the            specific condition may be determined by parameters such as a            specific CORESET index (e.g., the lowest index or the            highest index larger than 0 among CORESET indexes configured            for an active DL BWP) and/or pdcch-DMRS-ScramblingID (e.g.,            when it is set only by a function of cell-specific            information such as a cell ID) and/or precoderGranularity            (e.g., when it is set to allContiguousRBs) and/or duration            information (e.g., when it is set to a 1-symbol duration)            and/or frequencyDomainResources (e.g., when it indicates a            predetermined number of or more RBs). For example, a CORESET            associated with CORESET index 0 and/or a CORSET associated            with a DM-RS with pdcch-DMRS-ScramblingID configured only by            a function of cell-specific information may be the CORESET            satisfying the specific condition. For example, PDCCHs            configured to be monitored in a search space set associated            with the CORESET satisfying the specific condition may be            defined/configured as initial signals. For example, a PDCCH            DM-RS in every search space set (or search space, this may            also be applied to this subclause and various embodiments of            the present disclosure) associated with the CORESET may be            configured as an initial signal. In another example, for a            search space set satisfying a specific condition (e.g., the            index of a specific search space set such as the lowest of            CORESET indexes configured for an active DL BWP and/or a            monitoring occasion interval of k or fewer slots/symbols            and/or a specific aggregation level and/or a CSS and/or a            specific DCI format such as DCI format 2_0 and/or            configuration of a CORESET at a specific symbol position in            a slot) among search space sets associated with the CORESET,            a PDCCH DM-RS in a CORESET associated with the search space            set may be configured as an initial signal. In another            example, when the PDCCH DM-RS in the CORESET associated with            the search space set satisfying the specific condition is            configured, the UE may determine the PDCCH DM-RS as an            initial signal. For example, the search space set satisfying            the specific condition may be determined by parameters such            as a specific search space set index (e.g., the lowest index            or the lowest index larger than 0, among search space set            indexes configured for an active DL BWP) and/or a monitoring            occasion interval (e.g., k or fewer slots/symbols) and/or an            aggregation level (e.g., including a specific aggregation            level such as AL=16) and/or searchSpaceType (e.g., CSS type)            and/or a configuration for a specific DCI format (e.g., DCI            format 2_0/1/2/3 and/or a DCI format indicating a COT            structure) and/or a monitoring symbol index in a slot (e.g.,            symbol 0, symbol 7, or the like). In another example, when a            PDCCH DM-RS in a CORESET satisfying a specific condition            among CORESETs associated with search space sets satisfying            a specific condition is configured, the UE may determine the            PDCCH DM-RS as an initial signal.    -   CSI-RS (channel state information-reference signal): In an        exemplary embodiment, the UE may be configured with a specific        CSI-RS as an initial signal by the BS. In another example, when        a CSI-RS satisfying a specific condition is configured, the UE        may determine the CSI-RS as an initial signal. For example, the        CSI-RS satisfying the specific condition may be determined by a        configuration such as a configured usage (e.g., tracking and/or        RRM measurement and/or CSI acquisition/obtaining and/or beam        management) and/or a frequency band (e.g., a specific number of        or more RBs) and/or a monitoring occasion interval (e.g., equal        to or less than k slots/symbols) and/or a parameter involved in        a sequence initialization signal (e.g., set by a function of        only a cell-specific parameter such as a cell ID irrespective of        a UE-specific parameter).

According to various embodiments of the present disclosure, when the UEdiscovers the initial signal, the UE may perform PDCCH monitoring and/orCSI-RS reception and/or DL semi-persistent scheduling (SPS)-based signalreception, considering at least a specific duration to be DL-directed.

For example, the specific duration may be X symbol(s) or slot(s) from asymbol in which the initial signal has been discovered (in the case ofmultiple symbols (a plurality of symbols)), the starting or endingsymbol), and may be considered to be DL-directed.

For example, the value of X may be configured/indicated or predefined.

In another example, the specific duration may be an entire slot (fromthe starting/ending symbol of the initial signal in the slot to theending symbol of the slot) including the symbol in which the initialsignal has been discovered (in the case of multiple symbols (a pluralityof symbols), the starting or ending symbol) and the following Ysymbol(s) or slot(s), and may be considered to be DL-directed.

For example, the value of Y may be configured/indicated or predefined.

According to various embodiments of the present disclosure, a differentinitial signal sequence and/or a different initial signal may be definedaccording to information about X and/or Y.

For example, the information about X and/or Y may be received by using adifferent linear feedback shift register (LFSR) initial value and/or adifferent polynomial for generating an m-sequence such as a PSS/SSS.

In another example, X and/or Y may be used as a parameter for sequenceinitialization of a pseudo-random sequence such as a DM-RS/CSI-RS.

In another example, it may be configured that X=1 (symbol or slot) for aDM-RS linked to CORESET index 1, and X=2 (symbols or slots) for a DM-RSlinked to CORESET index 2. That is, when the DM-RS linked to CORESETindex 1 is discovered (used) as an initial signal, X=1 (symbol or slot).When the DM-RS linked to CORESET index 2 is discovered (used) as aninitial signal, X=2 (symbols or slots). In other words, for example,when the DM-RS linked to CORESET index 1 is discovered (used) as aninitial signal, the specific duration is one symbol or slot. When theDM-RS linked to CORESET index 2 is discovered (used) as an initialsignal, the specific duration is two symbols or slots. On the contrary,it may be configured that X=2 (symbols or slots) for a DM-RS linked toCORESET index 1, and X=1 (symbol or slot) for a DM-RS linked to CORESETindex 2.

In another example, information delivered in the initial signal (e.g.,PSS/SSS and/or DM-RS/CSI-RS) may include information (e.g., an offsetand a duration) about a UL duration as well as information about a DLduration.

3.1.1.2. [Method #1-2A] DL Tx Burst is Obtained Based on PDCCH

According to various embodiments of the present disclosure, specificPDCCH(s) may be defined as an initial signal. For example, upondiscovery of the initial signal, the UE may recognize the presence of aDL Tx burst. In another example, upon discovery of specific PDCCH(s),the UE may recognize the presence of a DL Tx burst.

In an exemplary embodiment, the specific PDCCH(s) may be PDCCH(s) (PDCCHcandidate(s)) linked to a CORESET satisfying a specific condition. Forexample, the CORESET satisfying the specific condition may be determinedby parameters such as a specific CORESET index (e.g., the lowest indexor the lowest index larger than 0, among CORESET indexes configured foran active DL BWP) and/or pdcch-DMRS-ScramblingID (e.g., when it is setby a function of only cell-specific information such as a cell ID)and/or precoderGranularity (e.g., when it is set to allContiguousRBs)and/or duration information (e.g., when it is set to 1-symbol duration)and/or frequencyDomainResources (e.g., when it indicates a predeterminednumber of or more RBs). For example, a CORESET associated with CORESETindex 0 and/or a CORESET associated with a DM-RS withpdcch-DMRS-ScramblingID configured by a function of only cell-specificinformation may be the CORESET satisfying the specific condition.

For example, PDCCHs configured to be monitored in a search space setassociated with the CORESET satisfying the specific condition may bedefined/configured as initial signals. For example, specific PDCCH(s) inevery search space set linked to the CORESET may be configured as aninitial signal.

In another example, for a search space set satisfying a specificcondition (e.g., the index of a specific search space set such as thelowest of CORESET indexes configured for an active DL BWP and/or amonitoring occasion interval of k or fewer slots/symbols and/or aspecific aggregation level and/or a CSS and/or a specific DCI formatsuch as DCI format 2_0 and/or configuration of a CORESET at a specificsymbol position in a slot) among search space sets associated with theCORESET, specific PDCCH(s) in a CORESET associated with the search spaceset may be configured as an initial signal.

In another example, when specific PDCCH(s) (PDCCH candidate(s)) areconfigured in the CORESET associated with the search space setsatisfying the specific condition, the UE may determine the PDCCH(s) asan initial signal.

For example, the search space set satisfying the specific condition maybe determined by parameters such as a specific search space set index(e.g., the lowest index or the lowest index larger than 0, among searchspace set indexes configured for an active DL BWP) and/or a monitoringoccasion interval (e.g., k or fewer slots/symbols) and/or an aggregationlevel (e.g., including a specific aggregation level such as AL=16)and/or searchSpaceType (e.g., CSS type) and/or a configuration for aspecific DCI format (e.g., DCI format 2_0/1/2/3 and/or a DCI formatindicating a COT structure) and/or a monitoring symbol index in a slot(e.g., symbol 0, symbol 7, or the like).

In another example, when specific PDCCH(s) (PDCCH candidate(s)) isconfigured in a CORESET satisfying a specific condition among CORESETsassociated with search space sets satisfying a specific condition, theUE may determine the PDCCH as an initial signal.

According to various embodiments of the present disclosure, when the UEdiscovers the initial signal, the UE may perform PDCCH monitoring and/orCSI-RS reception and/or DL SPS-based signal reception, considering atleast a specific duration to be DL-directed.

For example, the specific duration may be X symbol(s) or slot(s) from asymbol in which the initial signal has been discovered (in the case ofmultiple symbols (a plurality of symbols), the starting or endingsymbol), and may be considered to be DL-directed.

For example, the value of X may be configured/indicated or predefined.

In another example, the specific duration may be an entire slot (or fromthe starting/ending symbol of the initial signal in the slot to the lastsymbol of the slot) including a symbol in which the initial signal hasbeen discovered (in the case of multiple symbols (a plurality ofsymbols), the starting or ending symbol) and the following Y symbol(s)or slot(s), and may be considered to be DL-directed.

For example, the value of Y may be configured/indicated or predefined.

According to various embodiments of the present disclosure, theinformation about X and/or Y may be included in the initial signal. Forexample, the information about X and/or Y may be indicated by DCIpayload in the initial signal (i.e., the information may be included inthe DCI payload).

In another example, the information delivered in the initial signal(e.g., the PDCCH) may include information about a UL duration (e.g., anoffset and a duration) as well as information about a DL duration.

When a PDCCH is defined as an initial signal or a DL Tx burst isacquired through the PDCCH as in the above method, the UE may notsucceed in decoding the PDCCH due to a PDCCH CRC error or the like,although the UE has discovered a DM-RS associated with the PDCCH. Inthis case, the UE may perform, for example, a DM-RS-based DL Tx burstreception operation as in [Method #1-1A]. Alternatively, for example,the UE may attempt to detect a PDCCH defined as an initial signal (orfor acquiring a DL Tx burst) in the next PDCCH monitoring occasion,considering that there is no DL Tx burst for the UE.

In the above method, when a plurality of PDCCHs (PDCCH candidates) aredefined as an initial signal for a specific duration (e.g., one symbolor slot, or X/Y symbol(s) or slot(s)) or when a DL Tx burst is acquiredthrough a plurality of PDCCHs (PDCCH candidates), upon discovery of atleast one of the PDCCHs, the UE may perform PDCCH monitoring and/orCSI-RS reception and/or DL SPS-based signal reception, considering atleast the specific duration to be DL-directed.

In an exemplary embodiment, when a DL duration and/or a UL duration isindicated to the UE in the above-described [Method #1-1A] and [Method#1-2A], the DL duration and/or the UL duration may be interpreteddifferently depending on a signal and/or a channel defined as an initialsignal.

For example, when a CSI-RS for tracking is discovered (used) as aninitial signal, X=1 (symbol or slot), and when a PDCCH is discovered(used) as an initial signal, X=2 (symbols or slots). That is, forexample, when the CSI-RS for tracking is discovered (used) as an initialsignal, the DL duration and/or the UL duration may be one symbol orslot, and when the PDCCH is discovered (used) as an initial signal, theDL duration and/or the UL duration may be two symbols or slots.

For example, a different initial signal may be defined according to aslot/symbol index. For example, an initial signal may be defined for aneven-numbered slot according to [Method #1-1A] and for an odd-numberedslot according to [Method #1-2A].

In an exemplary embodiment, when a DL Tx burst is acquired based on a DLsignal and/or a PDCCH as in the above-described [Method #1-1A] and[Method #1-2A], a different method may be applied depending on theinside or outside of a COT of the BS. That is, for example, differentmethods may be applied to the inside and outside of the COT of the BS.For example, a DL Tx burst may be acquired inside the COT of the BSbased on the exemplary embodiment described in [Method #1-1A]. Forexample, a DL Tx burst may be acquired outside the COT of the BS basedon the exemplary embodiment described in [Method #1-2A].

For example, outside the COT and/or in the first k slot(s) of the COT(e.g., k=1 and the value of k may be predefined or indicated/configuredto/for the UE by L1 signaling and/or higher-layer signalling), the UEmay acquire a DL Tx burst and/or information about the DL Tx burst byusing a specific PDCCH and/or DM-RS linked to a specific CORESET orsearch space set for which precoderGranularity is set toallContiguousRBs and/or frequencyDomainResources indicates a specificnumber of or more RBs (e.g., 48 RBs for a 30-kHz SCS and 96 RBs for a15-kHz SCS where the SCS may be related to an unlicensed band in which aDL Tx burst is transmitted and received).

For example, the first k slot(s) of the COT may be the first k slot(s)inside the COT. For example, k may be associated with a processing timeof the UE for determining the inside or outside of the COT and/orchanging an operation accordingly. For example, the first k slot(s) ofthe corresponding COT is inside the COT, but considering the processingtime, it may be difficult for the UE to immediately change theoperation. Therefore, according to an exemplary embodiment, the UE mayacquire a corresponding DL Tx burst and/or information on the DL Txburst based on a similar operation to for the outside of the COT, in thefirst k slot(s) of the COT.

For example, it may be desirable in terms of reliable reception todesign a corresponding signal/channel (e.g., DL signal and/or PDCCH) tooccupy a significant amount of frequency-axis resources.

On the other hand, for example, it may be desirable to design thesignal/channel to utilize less frequency resources inside the COT and/orafter the first k slot(s) of the COT, when considering transmissions ofother DL signals/channels such as other PDCCHs.

Therefore, for example, the UE may acquire a DL Tx burst and/orinformation about the DL Tx burst by using a specific PDCCH and/or DM-RSlinked to a specific CORESET or search space set for which“precoderGranularity is not set to allContiguousRBs and/or which doesnot satisfy the condition that frequencyDomainResources indicates aspecific number or more RBs (e.g., 48 RBs for a 30-kHz SCS and 96 RBsfor a 15-kHz SCS)”, inside the COT and/or after the first k slot(s) ofthe COT.

More specifically, for example, it is assumed that COT information(e.g., time-axis information and/or frequency-axis information about theCOT) of the BS may be transmitted in a DCI format scrambled with aCOT-RNTI. In this case, for example, it may be configured that the DCIformat scrambled with the COT-RNTI is transmitted in CORESET #X forwhich precoderGranularity is set to allContiguousRBs andfrequencyDomainResources indicates 48 RBs for a 30-kHz SCS or searchspace set #X linked to the CORESET. Further, for example, it may beconfigured that the DCI format scrambled with the COT-RNTI istransmitted in CORESET #Y for which precoderGranularity is not set toallContiguousRBs and frequencyDomainResources indicates 24 RBs for a30-kHz SCS or search space set #Y linked to the CORESET.

For example, the BS may transmit the DCI format scrambled with theCOT-RNTI in CORESET #X or the search space set #X linked to the CORESET,outside the COT and/or in the first k slot(s) of the COT. Further, forexample, the BS may transmit the DCI format scrambled with the COT-RNTIin CORESET #Y or the search space set #Y linked to the CORESET, insidethe COT and/or after the first k slot(s) of the COT. According to thisexemplary embodiment, resources available for transmission of a DLchannel/signal such as a PDCCH other than the DCI format and/or a PDSCHinside the COT may be efficiently used.

3.1.2. Operation on Transmitter Side (Entity B)

3.1.2.1. [Method #1-1B] DL Tx Burst is Transmitted Based on DL Signal

According to various embodiments of the present disclosure, specific DLsignal(s) may be defined as an initial signal. According to variousembodiments of the present disclosure, the BS may indicate the presenceof a DL Tx burst by transmitting an initial signal after the BS succeedsin a CAP. In another example, the BS may indicate the presence of a DLTx burst by transmitting specific DL signal(s) after the BS succeeds ina CAP. For example, the specific DL signal(s) may be all or a part ofthe signals proposed in [Method #1-1A] according to various embodimentsof the present disclosure.

In an exemplary embodiment, when the BS transmits the initial signal,the BS may perform a DL transmission at least for a specific duration.

For example, the specific duration may be X symbol(s) or slot(s) from asymbol in which the initial signal has been discovered (in the case ofmultiple symbols (a plurality of symbols)), the starting or endingsymbol), and may be considered to be DL-directed.

For example, the value of X may be configured/indicated or predefinedfor the UE by the BS.

In another example, the specific duration may be an entire slot (or fromthe starting/ending symbol of the slot to the last symbol of the slot)including the symbol in which the initial signal has been discovered (inthe case of multiple symbols (a plurality of symbols), the starting orending symbol) and the following Y symbol(s) or slot(s), and may beconsidered to be DL-directed.

For example, the value of Y may be configured/indicated or predefinedfor the UE by the BS.

According to various embodiments of the present disclosure, a differentinitial signal sequence and/or a different initial signal may be definedaccording to information about X and/or Y.

For example, the information about X and/or Y may be received by using adifferent LFSR initial value and/or a different polynomial forgenerating an m-sequence such as a PSS/SSS.

In another example, X and/or Y may be used as a parameter for sequenceinitialization of a pseudo-random sequence such as a DM-RS/CSI-RS.

In another example, information delivered in the initial signal (e.g.,PSS/SSS and/or DM-RS/CSI-RS) may include information (e.g., an offsetand a duration) about a UL duration as well as information about a DLduration.

3.1.2.2. [Method #1-2B] DL Tx Burst is Transmitted Based on PDCCH

According to various embodiments of the present disclosure, specificPDCCH(s) may be defined as an initial signal. According to variousembodiments of the present disclosure, the BS may indicate the presenceof a DL Tx burst by transmitting an initial signal after succeeding in aCAP. In another example, the BS may indicate the presence of a DL Txburst by transmitting specific PDCCH(s) after succeeding in a CAP. Forexample, the specific DL signal(s) may be at least a part or all ofPDCCH(s) (PDCCH candidate(s)) proposed in the afore-described [Method#1-2A] according to various embodiments of the present disclosure.

In an exemplary embodiment, once the BS transmits the initial signal,the BS may perform a DL transmission during at least a specificduration.

For example, the specific duration may be X symbol(s) or slot(s) from asymbol in which the initial signal has been discovered (in the case ofmultiple symbols (a plurality of symbols), the starting or endingsymbol), and may be considered to be DL-directed.

For example, the value of X may be configured/indicated or predefinedfor the UE by the BS.

In another example, the specific duration may be an entire slot (or fromthe starting/ending symbol of the slot to the last symbol of the slot)including a symbol in which the initial signal has been discovered (inthe case of multiple symbols (a plurality of symbols), the starting orending symbol) and the following Y symbol(s) or slot(s), and may beconsidered to be DL-directed.

For example, the value of Y may be configured/indicated or predefinedfor the UE by the BS.

According to various embodiments of the present disclosure, informationabout X and/or Y may be included in the initial signal. For example, theinformation about X and/or Y may be indicated by DCI payload in theinitial signal (i.e., the information may be included in the DCIpayload).

In another example, the information delivered in the initial signal(e.g., the PDCCH) may include information about a UL duration (e.g., anoffset and a duration) as well as information about a DL duration.

In an exemplary embodiment, when a DL Tx burst is acquired based on a DLsignal and/or a PDCCH as in the above-described [Method #1-1A] and[Method #1-2A], a different method may be applied depending on theinside or outside of a COT of the BS. That is, for example, differentmethods may be applied to the inside and outside of the COT of the BS.For example, a DL Tx burst may be acquired inside the COT of the BSbased on the exemplary embodiment described in [Method #1-1A]. Forexample, a DL Tx burst may be acquired outside the COT of the BS basedon the exemplary embodiment described in [Method #1-2A].

For example, outside the COT and/or in the first k slot(s) of the COT(k=1 and the value of k may be predefined or indicated/configured to/forthe UE by L1 signaling and/or higher-layer signalling), the BS maytransmit information about a DL Tx burst by using a specific PDCCHand/or DM-RS linked to a specific CORESET or search space set for whichprecoderGranularity is set to allContiguousRBs and/orfrequencyDomainResources indicates a specific number of or more RBs(e.g., 48 RBs for a 30-kHz SCS and 96 RBs for a 15-kHz SCS where the SCSmay be related to an unlicensed band in which a DL Tx burst istransmitted and received).

For example, the first k slot(s) of the COT may be the first k slot(s)inside the COT. For example, k may be associated with a processing timeof the UE for determining the inside or outside of the COT and/orchanging an operation accordingly. For example, the first k slot(s) ofthe corresponding COT is inside the COT, but considering the processingtime, it may be difficult for the UE to immediately change theoperation. Therefore, according to an exemplary embodiment, the UE mayacquire a corresponding DL Tx burst and/or information on the DL Txburst based on a similar operation to for the outside of the COT, in thefirst k slot(s) of the COT.

For example, it may be desirable in terms of reliable reception todesign a corresponding signal/channel (e.g., DL signal and/or PDCCH) tooccupy a significant amount of frequency-axis resources.

On the other hand, for example, it may be desirable to design thesignal/channel to utilize less frequency resources inside the COT and/orafter the first k slot(s) of the COT, when considering transmissions ofother DL signals/channels such as other PDCCHs.

Therefore, for example, a DL Tx burst and/or information about the DL Txburst may be transmitted (to the UE by the BS) by using a specific PDCCHand/or DM-RS linked to a specific CORESET or search space set for which“precoderGranularity is not set to allContiguousRBs and/or which doesnot satisfy the condition that frequencyDomainResources indicates aspecific number or more RBs (e.g., 48 RBs for a 30-kHz SCS and 96 RBsfor a 15-kHz SCS)”, inside the COT and/or after the first k slot(s) ofthe COT.

More specifically, for example, it is assumed that COT information(e.g., time-axis information and/or frequency-axis information about theCOT) of the BS may be transmitted in a DCI format scrambled with aCOT-RNTI. In this case, for example, it may be configured that the DCIformat scrambled with the COT-RNTI is transmitted in CORESET #X forwhich precoderGranularity is set to allContiguousRBs andfrequencyDomainResources indicates 48 RBs for a 30-kHz SCS or searchspace set #X linked to the CORESET. Further, for example, it may beconfigured that the DCI format scrambled with the COT-RNTI istransmitted in CORESET #Y for which precoderGranularity is not set toallContiguousRBs and frequencyDomainResources indicates 24 RBs for a30-kHz SCS or search space set #Y linked to the CORESET.

For example, the BS may transmit the DCI format scrambled with theCOT-RNTI in CORESET #X or the search space set #X linked to the CORESET,outside the COT and/or in the first k slot(s) of the COT. Further, forexample, the BS may transmit the DCI format scrambled with the COT-RNTIin CORESET #Y or the search space set #Y linked to the CORESET, insidethe COT and/or after the first k slot(s) of the COT. According to thisexemplary embodiment, resources available for transmission of a DLchannel/signal such as a PDCCH other than the DCI format and/or a PDSCHinside the COT may be efficiently used.

In [Method #1-1A], [Method #1-2A], [Method #1-1B], and [Method #1-2B]according to various embodiments of the present disclosure, an initialsignal may include a plurality of symbols. That is, according to variousembodiments of the present disclosure, the initial signal may betransmitted and received in a plurality of symbols.

For example, the initial signal may be repeated in each symbol.

For example, a different initial signal may be defined for each symbol.

For example, the initial signal may be repeated and multiplexed by atime-axis orthogonal cover code (OCC) in each symbol.

In [Method #1-1A], [Method #1-2A], [Method #1-1B], and [Method #1-2B]according to various embodiments of the present disclosure, a pluralityof signals/channels may be defined as an initial signal even in aspecific duration (e.g., one symbol or slot or X/Y symbols or slots).

Alternatively, according to various embodiments of the presentdisclosure, the UE may recognize a DL Tx burst based on a plurality ofsignals/channels within a specific duration.

Alternatively, according to various embodiments of the presentdisclosure, a different signal/channel may be defined as an initialsignal in each specific duration (e.g., one symbol or slot or X/Ysymbols or slots).

With reference to the example of FIG. 22 , various embodiments of thepresent disclosure will be described below in greater detail.

FIG. 22 is a diagram illustrating an exemplary structure of transmittingand receiving an initial signal according to various embodiments of thepresent disclosure.

Referring to FIG. 22 , for example, a BS may configure an initial signalwith a half-slot periodicity for a first UE (UE1), and an initial signalwith a 1-slot periodicity for a second UE (UE2).

For example, it may be predefined or signalled that when the initialsignal is detected in a specific slot, the entire specific slot may beused for DL.

For example, after succeeding in a CAP, the BS may configure a COT tospan 2.5 slots from the middle of slot #n+1 and transmit a DL Tx burst.

For example, when UE1 detecting the initial signal with the half-slotperiodicity succeeds in detecting the initial signal in the middle ofslot #n+1, UE1 may perform a DL reception on the assumption that atleast the slot is DL-directed.

Further, for example, when UE2 detecting the initial signal in everyslot (with the 1-slot periodicity) succeeds in detecting the initialsignal in slot #n+2, UE2 may perform a DL reception on the assumptionthat at least the slot is DL-directed.

For example, even for a specific UE, a different initial signal may bedefined for each slot and/or slot group and/or symbol and/or symbolgroup.

For example, a PDCCH may be configured as an initial signal in a slot inwhich a CSS is configured. For example, a CSI-RS for tracking may beconfigured as an initial signal in a slot in which a USS is configured.

On the contrary, a CSI-RS for tracking may be configured as an initialsignal in a slot in which a CSS is configured. For example, a PDCCH maybe configured as an initial signal in a slot in which a USS isconfigured.

In another example, for an initial access UE (i.e., a UE which hasperformed/is performing initial access), a PDCCH may bedefined/configured as an initial signal, and then a new signal/channelmay be defined/configured as an initial signal by a configuration.

In another example, a CSI-RS for tracking may be defined/configured asan initial signal for an RRC-connected UE, and a PSS/SSS and/or a PDCCHmay be defined/configured as an initial signal for other UEs (e.g., anRRC-inactive and/or RRC-idle UE).

On the contrary, for example, a PSS/SSS and/or a PDCCH may bedefined/configured as an initial signal for an RRC-connected UE, and aCSI-RS for tracking may be defined/configured as an initial signal forother UEs (e.g., an RRC-inactive and/or RRC-idle UE).

In another example, a PDCCH DM-RS may be defined/configured as aninitial signal for a UE operating for DL only in an unlicensed-band NRcell, and a PDCCH (indicating a DL/UL direction and/or a COT structure)may be defined/configured as an initial signal for a UE operating forboth DL and UL in the unlicensed-band NR cell.

3.2. Method of Controlling PDCCH Monitoring Periodicity and/or TimeInstance

FIG. 27 is a diagram illustrating an exemplary method of transmittingand receiving a PDCCH according to various embodiments of the presentdisclosure.

Referring to FIG. 27 , in operation 2701 according to an exemplaryembodiment, a BS may perform a DL cap for an unlicensed band to transmita DL signal/channel such as a PDCCH to a UE. For example, the DL CAP maybe one or more of the afore-described various DL CAPs for DLtransmission.

In operation 2703 according to an exemplary embodiment, when the BSdetermines from the DL CAP that the unlicensed band is available (or achannel configured in the unlicensed band is idle), the BS may transmita PDCCH to the UE in the unlicensed band (or on the channel configuredin the unlicensed band) based on a method according to variousembodiments of the present disclosure.

For example, a PDCCH monitoring periodicity and/or time instance for theUE may be determined based on a later-described method according tovarious embodiments of the present disclosure. In operation 2705according to an exemplary embodiment, the UE may monitor and/or decodethe PDCCH received form the BS based on the determined PDCCH monitoringperiodicity and/or time instance.

For example, the UE may transmit and receive a signal scheduled by thereceived PDCCH (e.g., DCI) to and from the BS. For example, when the UEis to transmit a specific signal to the BS, the UE may transmit thespecific signal based on the result of a UL CAP. For example, the UL CAPmay be one or more of the afore-described various UL CAPs for ULtransmission.

For example, in operation 2703 according to the above-describedexemplary embodiment, the BS may transmit the PDCCH to the UE inconsideration of the PDCCH monitoring periodicity for the UE.

Now, a description will be given of a specific operation of a UE and/ora BS based on a PDCCH transmission and reception method according tovarious embodiments of the present disclosure.

For example, a time when the BS succeeds in a CAP may not be predicted.Therefore, it may be favorable in terms of efficient channel occupancyto set a PDCCH monitoring periodicity and/or time instance interval tobe very short.

On the contrary, for example, because setting of a short PDCCHmonitoring periodicity and/or time instance interval may result in greatpower consumption of the UE for PDCCH monitoring, it may be favorable interms of power consumption of the UE to set a relatively long PDCCHmonitoring periodicity and/or time instance interval.

Various embodiments of the present disclosure may provide specificmethods of controlling a PDCCH monitoring periodicity and/or timeinstance interval in consideration of the above-described aspects.

In the following description of various embodiments of the presentdisclosure in this subclause, a DL COT structure may be obtained throughan initial signal as described in subclause 3.1. Alternatively, forexample, the DL COT structure may be acquired through DCI format 2_0and/or a separate DCI format.

3.2.1. Operation of Receiver Side (Entity A)

3.2.1.1. [Method #2-1A] Method of Controlling PDCCH Monitoring Periodand/or Time Instance Interval According to Length of First Slot of DLCOT

For example, when the first slot of a DL COT is too short, it may bevery difficult to control a PDCCH monitoring periodicity and/or timeinstance interval immediately starting in the following slot (or after Kslots), in terms of UE implementation (e.g., in terms of a processingtime of the UE).

In this regard, according to various embodiments of the presentdisclosure, for example, when the length of the first slot of a DL COTis equal to or less than or less than N symbols (e.g., N=3), the UE mayperform PDCCH monitoring with a (PDCCH monitoring) periodicity appliedto the outside of the DL COT in the slot to the next slot (immediatelyfollowing the slot) (and/or the following K slots).

On the contrary, according to various embodiments of the presentdisclosure, for example, when the length of the first slot of the DL COTis equal to or larger than or larger than N symbols (e.g., N=3), the UEmay perform PDCCH monitoring with the (PDCCH monitoring) periodicityapplied to the outside of the DL COT, only in the slot (and/or the slotto the (immediately) following K−1 slots). For example, the UE mayperform PDCCH monitoring with a (PDCCH monitoring) periodicityconfigured for the inside of the DL COT, starting in the next slot(and/or the following K slots).

For example, the UE may switch to PDCCH monitoring with the (PDCCHmonitoring) periodicity configured for the inside of the DL COT,starting in the first of the slots following the corresponding slot(e.g., from the beginning and/or boundary of the first slot).

For example, the above-described N may be set to a larger value than aprocessing time of the UE for switching of a PDCCH monitoring operation.For example, N (the number of symbols) may be set to a value equal to orlarger than a time taken for the UE to switch the PDCCH monitoringoperation.

In an exemplary embodiment, it is assumed that multiple PDCCH monitoringoccasions (and/or CORESETs) are configured in a search space set withina specific slot.

For example, 0 & 4 & 7 & 11 are set as monitoring symbols (i.e., symbol#0 and symbol #4 and symbol #7 and symbol #11 are configured asmonitoring symbols) in a slot of a 1-symbol CORESET, and 0/1 & 4/5 & 7/8& 11/12 are set as monitoring symbols (i.e., symbol #0/1 and symbol #4/5and symbol #7/8 and symbol #11/12 are configured as monitoring symbols)in a slot of a 2-symbol CORESET.

According to various embodiments of the present disclosure, based on theassumption, when the length of the first slot of a discovered DL COT isequal to or less than (or less than) 3 symbols, the UE may perform PDCCHreception in multiple PDCCH monitoring occasions (and/or CORESETs) witha configured periodicity (e.g., the periodicity of monitoring symbols inthe above 1-symbol/2-symbol CORESET) even a slot in the correspondingslot to the next slot. According to various embodiments of the presentdisclosure, the UE may perform PDCCH reception only in the earliestsymbol area (and/or CORESET) among multiple PDCCH monitoring occasions(and/or CORESETs) in a slot, starting in the next slot. For example, thePDCCH may be received only in the earliest symbol #0 of the monitoringsymbols in the slot of the 1-symbol CORESET, and only in the earliestsymbol #0/1 of the monitoring symbols in the slot of the 2-symbolCORESET. Accordingly, PDCCH occasions may be reduced.

On the contrary, according to various embodiments of the presentdisclosure, based on the assumption, when the length of the first slotof a discovered DL COT is larger than (or equal to or larger than) 3symbols, the UE may perform PDCCH reception in multiple PDCCH monitoringoccasions (and/or CORESETs) with a periodicity even within the slot andonly for the slot. According to various embodiments of the presentdisclosure, the UE may perform PDCCH reception only in the earliestsymbol area (and/or CORESET) among multiple PDCCH monitoring occasions(and/or CORESETs) in a slot, starting from the next slot.

For a 1-symbol CORESET, for example, when the length of the first slotof a discovered DL COT is equal to or less than 3 symbols, the UE mayreceive a PDCCH based on PDCCH monitoring in monitoring symbols 0 & 4 &7 & 11 in the corresponding slot to the next slot, and based on PDCCHmonitoring in monitoring symbol 0 in slots following the next slot. Onthe contrary, when the length of the first slot of the discovered DL COTis larger than 3 symbols, the UE may receive a PDCCH based on PDCCHmonitoring in monitoring symbols 0 & 4 & 7 & 11 only in thecorresponding slot, and based on PDCCH monitoring in monitoring symbol 0in slots following the slot.

For a 2-symbol CORESET, for example, when the length of the first slotof a discovered DL COT is equal to or less than 3 symbols, the UE mayreceive a PDCCH based on PDCCH monitoring in monitoring symbols 0/1 &4/5 & 7/8 & 11/12 in the corresponding slot to the next slot, and basedon PDCCH monitoring in monitoring symbol 0/1 in slots following the nextslot. On the contrary, when the length of the first slot of thediscovered DL COT is larger than 3 symbols, the UE may receive a PDCCHbased on PDCCH monitoring in monitoring symbols 0/1 & 4/5 & 7/8 & 11/12only in the corresponding slot, and based on PDCCH monitoring inmonitoring symbol 0/1 in slots following the slot.

For example, when monitoring occasions of different periodicities areconfigured for multiple search space sets, the above-described variousembodiments of the present disclosure may be applied to specific searchspace set(s).

For example, the above-described various embodiments of the presentdisclosure may be applied to all search space set(s) in which PDCCHmonitoring occasions are configured at an interval less than a specificthreshold (e.g., one slot) among multiple search space sets.

For example, it is assumed that PDCCH monitoring is configured at aninterval of 2 slots in search space set #0, at an interval of 2 symbolsin search space set #1, and at an interval of 7 symbols in search spaceset #2. That is, in this example, PDCCH monitoring occasions areconfigured at a larger interval than a specific threshold in searchspace set #0, and PDCCH monitoring occasions are configured at a smallerinterval than the specific threshold in search space set #1/2.

In this case, the UE may perform PDCCH monitoring at the configuredinterval only in some starting slot(s) of a DL COT in each search spaceset #0/1/2. In slot(s) following the corresponding slot(s), PDCCHmonitoring is performed at an interval of one slot, particularly in theearliest symbols (i.e., CORESET duration) of each slot in search spaceset #1/2 (whereas PDCCH monitoring may be performed still at an intervalof 2 slots in search space set #0).

3.2.1.2. [Method #2-2A] Method of Controlling PDCCH MonitoringPeriodicity and/or Time Instance Interval

According to various embodiments of the present disclosure, a PDCCHmonitoring periodicity and/or time instance interval may be controlledexplicitly by UE-specific DCI and/or cell-specific DCI (e.g., explicitsignaling). According to various embodiments of the present disclosure,a PDCCH monitoring periodicity and/or time instance interval may becontrolled implicitly after detection of a predetermined signal (e.g., aDL burst, a DM-RS, a GC-PDCCH and/or a PDCCH) and/or based oninformation about a COT structure.

For example, multiple PDCCH monitoring intervals may be configured for aspecific search space set, and which one of the PDCCH monitoringintervals is to be used may be signaled. For example, when the PDCCHmonitoring interval is signaled by UE-specific DCI and/or cell-specificDCI, the UE-specific DCI and/or cell-specific DCI may includeinformation about the PDCCH monitoring interval.

In another example, search space sets may be divided into two or moregroups and a group including search space sets in which PDCCH monitoringwill be performed may be signaled. For example, each of the groups mayinclude one or more search space sets (one search space set may belongto two or more groups), and which one of the groups is used for PDCCHmonitoring may be signaled to the UE. For example, when the group issignaled by UE-specific DCI and/or cell-specific DCI, the UE-specificDCI and/or cell-specific DCI may include information about the group.For example, it may be configured that a different PDCCH monitoringperiodicity and/or time instance interval is applied to each group.

It may be difficult in terms of UE implementation for the UE toinstantly change the monitoring behavior after the time of receivingexplicit signaling (i.e., to change the monitoring behavior as soon asreceiving the explicit signaling). In this regard, according to variousembodiments of the present disclosure, the UE may perform PDCCHreception at an indicated PDCCH monitoring interval after Z symbols fromthe time of receiving the explicit signal (or from an HARQ-ACK feedback(for the explicit signaling)).

For example, it is assumed that PDCCH monitoring is configured at aninterval of 2 slots (type A) or 4 slots (type B) in search space set #0,at an interval of 2 symbols (type A) or 1 slot (type B) in search spaceset #1, and at an interval of 7 symbols (type A) or 1 slot (type B) insearch space set #2.

Based on the above assumption, for example, the BS may signal typeA/type B as a PDCCH monitoring periodicity by UE-specific DCI and/orcell-specific DCI. For example, the UE may apply the changed monitoringperiodicity after Z symbols from the time of receiving the UE-specificDCI and/or cell-specific DCI.

In another example, it is assumed that PDCCH monitoring is configured atan interval of 2 slots in search space set #0, at an interval of 2symbols in search space set #1, and at an interval of 7 symbols insearch space set #2.

Based on the above assumption, for example, group A (or group #0) mayset for search space set #0 and group B (or group #1) may set for searchspace set #1/2. For example, this configuration may be based onhigher-layer signalling. For example, the UE may receive informationindicating a group to which each search space set belongs, such asinformation indicating that search space set #0 belongs to group A,search space set #1 belongs to group B, and search space set #2 belongsto group B.

For example, the BS may signal which one of group A and group B (and/orwhich search space set related to the group) and/or which search spaceset is activated by UE-specific DCI and/or cell-specific DCI. Forexample, the UE may perform PDCCH monitoring in each active search spaceset (e.g., in each search space set included in an active group) after Zsymbols from the time of receiving the UE-specific DCI and/orcell-specific DCI.

That is, for example, the BS may indicate which one of group A and groupB is active by the UE-specific DCI and/or cell-specific DCI, at a grouplevel.

In another example, the BS may indicate which one of group A and group Ban activated search space set belongs to by UE-specific DCI and/orcell-specific DCI. In this case, the BS may also indicate which one ofthe search space sets included in the group is activated.

The above-described method according to various embodiments of thepresent disclosure may be applied in the same manner to a method ofcontrolling a PDCCH monitoring periodicity and/or time instanceaccording to a COT structure. In an exemplary embodiment, the UE mayidentify a COT structure by determining whether it is included in a DLTx burst by the afore-described initial signal according to variousembodiments of the present disclosure in subclause 3.1 (e.g., it isidentified based on information related to the length of a DL Tx burstincluded in the initial signal and/or when the initial signal isdiscovered, a DL Tx burst is determined to span a predetermined length)or DCI format 2_0 (e.g., delivered on a GC-PDCCH) and/or a separate DCIformat indicating the COT structure (e.g., delivered on a PDCCH and/or aGC-PDCCH).

Alternatively in an exemplary embodiment, a PDCCH monitoring periodicityand/or time instance interval may be controlled implicitly afterdetection of a predetermined signal (e.g., a DL burst, a DM-RS, aGC-PDCCH and/or a PDCCH) based on information about a COT structure.

For example, it is assumed that PDCCH monitoring is configured at aninterval of 2 slots (type A) or 4 slots (type B) in search space set #0,at an interval of 2 symbols (type A) or 1 slot (type B) in search spaceset #1, and at an interval of 7 symbols (type A) or 1 slot (type B) insearch space set #2.

Based on the assumption, for example, type B may be applied until beforea COT is discovered (and/or in some starting slot(s) of the DL COT), andtype A may be applied inside the COT (and/or in slot(s) after thestarting slot(s) of the DL COT).

In another example, it is assumed that PDCCH monitoring is configured atan interval of 2 slots in search space set #0, at an interval of 2symbols in search space set #1, and at an interval of 7 symbols insearch space set #2.

Based on the assumption, for example, search space set #0 may beconfigured as group A, and search space set #1/2 may be configured asgroup B. For example, group B may be applied until before a COT isdiscovered (and/or in some starting slot(s) of the DL COT), and group Amay be applied inside the COT (and/or in slot(s) after the startingslot(s) of the DL COT).

Alternatively, for example, it may be understood that group A is appliedinside a COT, and group B is applied outside the COT (e.g., before theCOT is discovered and/or after the COT ends).

Alternatively, for example, when a COT structure is identified by aninitial signal according to various embodiments of the presentdisclosure, a specific duration including X symbol(s) or slot(s) afterthe initial signal is discovered may be determined to be DL-directed, asdescribed before in subclause 3.1. Accordingly, it may be understoodthat group A is applied to the inside of the specific duration includingthe X symbol(s) or slot(s), and group B is applied to the outside of thespecific duration.

Search Space Set Switching Method—Embodiment 1

A description will be given of Embodiment 1 related to search space setswitching according to a method of controlling a PDCCH monitoringperiodicity and/or time instance interval according to variousembodiments of the present disclosure.

For example, switching between groups may amount to changing a group inwhich PDCCH monitoring is performed.

For example, after one or more of predetermined conditions aresatisfied, a UE performing PDCCH monitoring in group B may start PDCCHmonitoring in group A, and end the PDCCH monitoring in group B.

For example, the aspect of UE implementation may also be considered asdescribed before in [Method #2-1A] and/or [Method #2-1B]. For example,the UE performing PDCCH monitoring in group B may start PDCCH monitoringin group A and end the PDCCH monitoring in group B, N symbols after oneor more of the predetermined conditions are satisfied. For example, theUE may start PDCCH monitoring in group A and end PDCCH monitoring ingroup B, in the first slot after the N symbols (e.g., the beginningand/or boundary of the first slot), thereby switching the PDCCHmonitoring operation.

For example, N may be set to a larger value than a processing time ofthe UE for switching a PDCCH monitoring operation (e.g., search spaceset switching corresponding to starting PDCCH monitoring in group A andending PDCCH monitoring in group B). For example, N may be set to beequal to or larger than a time taken for the UE to switch the PDCCHmonitoring operation.

For example, the UE may be provided with two groups or at least twogroups of search space sets for a PDCCH (e.g., by higher-layersignalling such as RRC signalling). For example, the UE may be providedwith the group index of each search space set for the configured PDCCHmonitoring.

For example, the UE may be configured to switch between groups (e.g., byhigher-layer signalling such as RRC signalling).

For example, switching between groups may be indicated by at least oneof the following options (in other words, when one or more ofpredetermined conditions are satisfied, switching may occur betweengroups).

-   -   Opt 1: Implicit indication. For example, switching between        groups is implicitly indicated after detection of a        predetermined signal (e.g., a DL burst, a wideband (WB) DM-RS, a        GC-PDCCH, and/or a PDCCH) and/or based on information about a        COT structure.    -   Opt 2: Explicit indication. For example, switching between        groups is explicitly indicated based on a GC-PDCCH and/or a        PDCCH.

For example, search space set(s) (e.g., CSS set) other than a part ofconfigured groups may always be monitored by the UE, irrespective of asearch space set indication.

For example, a single search space set may be a member of one or more(e.g., two or more) groups. That is, a single search space set maybelong to only one group or two or more groups.

Search Space Set Switching Method—Embodiment 2

A description will be given of Embodiment 2 related to search space setswitching according to a method of controlling a PDCCH monitoringperiodicity and/or time instance interval according to variousembodiments of the present disclosure.

For example, the UE may be provided with the group index of eachconfigured search space set by a higher-layer parameter (e.g.,searchSpaceGroupIdList-r16), for PDCCH monitoring in a serving cellindicated by a higher-layer parameter (e.g.,searchSpaceSwitchingGroup-r16).

For example, when the UE is not provided with the higher-layer parameterfor search space sets (e.g., searchSpaceGroupIdList-r16) and/or thehigher-layer parameter (e.g., searchSpaceSwitchingGroup-r16) for PDCCHmonitoring in a serving cell, operations according to variousembodiments of the present disclosure as described below may not beapplied to PDCCH monitoring in a search space set.

For example, the UE may be provided with a timer value by a higher-layerparameter (e.g., searchSpaceSwitchingTimer-r16). For example, the UE maydecrement the timer value by one after each slot within an active DL BWPof a serving cell in which the UE monitors a PDCCH to detect DCI format2_0.

For example, when the UE is provided with a higher-layer parameter(e.g., SearchSpaceSwitchTrigger-r16) indicating the position of a searchspace set switching field in DCI format 2_0 for a serving cell anddetects DCI format 2_0 in a slot, the UE may operate as follows.

-   -   For example, if the UE does not monitor a PDCCH in search space        set(s) with group index 0 and the value of the search space set        field is 0, the UE may start PDCCH monitoring in the search        space set(s) with group index 0 in the serving cell in the first        slot after at least P1 symbols from the corresponding slot in        the active DL BWP of the serving cell, and stop PDCCH monitoring        in search space set(s) with group index 1.    -   For example, if the UE does not perform PDCCH monitoring in the        search space set(s) with group index 1 and the value of the        search space set field is 1, the UE may start PDCCH monitoring        in the search space set(s) with group index 1 in the serving        cell in the first slot after at least P1 symbols from the        corresponding slot in the active DL BWP of the serving cell,        stop PDCCH monitoring in search space set(s) with group index 0,        and set the timer value to a value provided by a higher-layer        parameter (e.g., searchSpaceSwitchingTimer-r16).    -   For example, if the UE performs PDCCH monitoring in the search        space set(s) with group index 1, the UE may start PDCCH        monitoring in the search space set(s) with group index 0 in the        serving cell at the beginning of the first slot after at least        P1 symbols from a slot in which the timer expires and/or the        last slot of the remaining channel occupancy duration for the        serving cell, indicated by DCI format 2_0, and stop PDCCH        monitoring in search space set(s) with group index 1.

For example, if the UE is not provided with the higher-layer parameter(e.g., SearchSpaceSwitchTrigger-r16), the UE operates as follows.

-   -   For example, when the UE detects a DCI format by PDCCH        monitoring in a search space set with group index 0 in a slot        and when the UE detects a DCI format by PDCCH monitoring in any        search space set, the UE may start PDCCH monitoring in the        search space set(s) with group index 1 in the serving cell and        stop PDCCH monitoring in search space set(s) with group index 0,        in the first slot after at least P2 symbols from the        corresponding slot in the active DL BWP of the serving cell.    -   For example, when the UE performs PDCCH monitoring in the search        space set(s) with group index 1, and after a slot in which the        timer expires and/or when the UE is provided with a search space        set for PDCCH monitoring to detect DCI, the UE may start PDCCH        monitoring in the search space set(s) with group index 0 and        stop PDCCH monitoring in search space set(s) with group index 1,        in the serving cell at the beginning of the first slot after at        least P2 symbols from the last slot of the remaining channel        occupancy duration for the serving cell, indicated by DCI format        2_0.

For example, the aspect of UE implementation may also be considered forP1/P2 as described before in [Method #2-1A] and/or [Method #2-1B]. Forexample, P1/P2 may be set to a larger value than a processing time ofthe UE for switching a PDCCH monitoring operation (e.g., search spaceset switching corresponding to starting PDCCH monitoring for a groupwith group index #0/1 and ending PDCCH monitoring for a group with groupindex #1/0.

3.2.2. Operation of Transmitter Side (Entity B)

3.2.2.1. [Method #2-1B] Method of Controlling PDCCH Monitoring Periodand/or Time Instance Interval According to Length of First Slot in DLCOT

For example, when the first slot of a DL COT is too short, it may bevery difficult to control a PDCCH monitoring periodicity and/or timeinstance interval immediately starting in the following slot (or after Kslots), in terms of BS implementation.

In this regard, according to various embodiments of the presentdisclosure, for example, when the length of the first slot of a DL COTis equal to or less than or less than N symbols (e.g., N=3), the BS maytransmit a PDCCH with a (PDCCH monitoring) periodicity applied to theoutside of the DL COT in the slot to the next slot (immediatelyfollowing the slot) (and/or the following K slots).

On the contrary, according to various embodiments of the presentdisclosure, for example, when the length of the first slot of the DL COTis equal to or larger than or larger than N symbols (e.g., N=3), the BSmay transmit a PDCCH with the (PDCCH monitoring) periodicity applied tothe outside of the DL COT only in the slot (and/or the slot to the(immediately) following K−1 slots). For example, the UE may performPDCCH monitoring with a (PDCCH monitoring) periodicity applied to theinside of the DL COT, starting in the slot next to the correspondingslot (and/or the K following slots).

For example, when monitoring occasions of different periodicities areconfigured for multiple search space sets, the above-described variousembodiments of the present disclosure may be applied to specific searchspace set(s).

For example, the above-described various embodiments of the presentdisclosure may be applied to all search space set(s) in which PDCCHmonitoring occasions are configured at an interval less than a specificthreshold (e.g., one slot) among multiple search space sets.

3.2.2.2. [Method #2-2B] Method of Controlling PDCCH MonitoringPeriodicity and/or Time Instance Interval

According to various embodiments of the present disclosure, a PDCCHmonitoring periodicity and/or time instance interval may be controlledexplicitly by UE-specific DCI and/or cell-specific DCI (e.g., explicitsignaling). According to various embodiments of the present disclosure,a PDCCH monitoring periodicity and/or time instance interval may becontrolled implicitly after detection of a predetermined signal (e.g., aDL burst, a DM-RS, a GC-PDCCH and/or a PDCCH) and/or based oninformation about a COT structure.

For example, multiple PDCCH monitoring intervals may be configured for aspecific search space set, and which one of the PDCCH monitoringintervals is to be used may be signaled. For example, when the PDCCHmonitoring interval is signaled by UE-specific DCI and/or cell-specificDCI, the UE-specific DCI and/or cell-specific DCI may includeinformation about the PDCCH monitoring interval.

In another example, search space sets may be divided into two or moregroups and a group including search space sets in which PDCCH monitoringwill be performed may be signaled. For example, each of the groups mayinclude one or more search space sets (one search space set may belongto two or more groups), and which one of the groups is used for PDCCHmonitoring may be signaled to the UE. For example, when the group issignaled by UE-specific DCI and/or cell-specific DCI, the UE-specificDCI and/or cell-specific DCI may include information about the group.For example, it may be configured that a different PDCCH monitoringperiodicity and/or time instance interval is applied to each group.

The methods of changing a PDCCH monitoring periodicity and/or timeinstance according to various embodiments of the present disclosure,such as [Method #2-1A], [Method #2-2A], [Method #2-1B], and [Method#2-2B], may be applied to both of self-carrier scheduling (SCS) andcross-carrier scheduling (CCS).

With reference to the examples of FIGS. 24, 25 and 26 , variousembodiments of the present disclosure may be described in greaterdetail.

FIGS. 24, 25 and 26 are diagrams illustrating PDCCH transmission andreception structures according to various embodiments of the presentdisclosure.

In the NR system, for example, a PDCCH monitoring occasion in a searchspace set configured for a scheduled cell (and/or an active BWP in acell which may be replaced with a BWP and/or active BWP and/or channeland/or CAP subband (in the cell) in the description of this subclauseand various embodiments of the present disclosure) is linked to a searchspace set configured for a scheduling cell with the same index as thesearch space set, and PDCCH monitoring is performed in the PDCCHmonitoring occasion.

Referring to FIG. 24 , for example, when a scheduling cell for cell 2 isconfigured as cell 1, a DCI format linked to search space set ID #0 ofcell 2 may be monitored in a PDCCH monitoring occasion configured insearch space set ID #0 of cell 1. In the description of this subclauseand various embodiments of the present disclosure, the expression searchspace set ID #X may be understood as identical to search space set #X.

For example, cell 2 may be on an unlicensed spectrum or a sharedspectrum.

For example, it is assumed that PDCCH monitoring at an interval of 2symbols (type A) or 1 slot (type B) is configured in search space set ID#0 for cell 2.

Based on the assumption, for example, it may be configured that type Bis applied before a COT is discovered (and/or in some starting slot(s)of the DL COT), and type A is applied inside the COT (and/or in slot(s)after the starting slot(s) of the DL COT).

Herein, for example, when cell 1 is configured as a scheduling cell forcell 2, it may be regulated that DCI monitoring linked to search spaceset ID #0 of cell 2 is performed twice per slot according to aconfiguration of search space set ID #0 of cell 1 before a COT isdiscovered in cell 2 (and/or in some starting slot(s) of the DL COT),and once per slot according to the configuration of search space set ID#0 of cell 2 inside the COT (and/or in slots after the starting slot(s)of the DL COT) (or more sparse PDCCH monitoring time instances betweenthe configuration of search space set ID #0 of cell 1 and theconfiguration of search space set ID #0 of cell 2).

In another example, it is assumed that group B is set for search spaceset ID #0 configured for cell 2.

Based on the assumption, for example, it may be configured that only asearch space set corresponding to group B is valid before a COT isdiscovered (and/or in some starting slot(s) of the DL COT), and only asearch space set corresponding to group A is valid (i.e., search spacesets corresponding to group B are invalid) inside the COT (and/or inslots after the starting slot(s) of the DL COT).

Herein, for example, DCI for cell 2 may be monitored in search space setID #0 configured in cell 1 before a COT for cell 2 is discovered (and/orin some starting slot(s) of the DL COT), and DCI for cell 2 may not bemonitored in search space set ID #0 configured in cell 1 inside the COT(and/or in slot(s) after the starting slot(s) of the DL COT).

Embodiment 1

Referring to FIG. 25 , for example, PDCCH monitoring occasions may beconfigured in search space set #0/1/2 as illustrated in FIG. 25 . Forexample, search space set #1 may be set to group A, and search space set#2 may be set to group B.

For example, it is assumed that a CORESET and/or a PDCCH DM-RS linked tosearch space set #0 is defined/configured as an initial signal and/or asignal from which transmission of a serving cell is recognized (by theUE).

Based on the assumption, for example, the UE may perform PDCCHmonitoring twice per slot according to a configuration of search spaceset #0.

For example, when the UE discovers a PDCCH and/or a PDCCH DM-RS insearch space set #0 in slot #n+1 and acquires information indicatingthat slots of up to slot #n+3 are DL slots from the PDCCH and/or anotherPDCCH, the UE may perform PDCCH monitoring (in the earliest timeduration among PDCCH monitoring occasions allocated to a slot) once perslot from slot #n+2, when performing PDCCH monitoring for search spaceset #0.

For example, the UE, which recognizes that the middle of slot #n+1 toslot #n+3 are DL slots, may perform PDCCH monitoring in PDCCH monitoringoccasions configured in search space set #2 during the first DL slot(i.e., slot #n+1), and in PDCCH monitoring occasions configured insearch space set #1 during the following DL slots (i.e., slot #n+2/3).

For example, when the UE discovers a PDCCH and/or a PDCCH DM-RS insearch space set #0 in slot #n+1 and acquires information indicatingthat slots of up to slot #n+3 are DL slots from the PDCCH and/or anotherPDCCH, the UE may not perform configured PDCCH monitoring in searchspace set #0 in slot #n+1 before the discovery of the PDCCH and/or thePDCCH DM-RS and/or in search space set #1 and/or search space set #2after slot #n+3.

Embodiment 2

According to various embodiments of the present disclosure, when the UEperforms PDCCH monitoring, a different PDCCH monitoring time pattern maybe configured for each phase as follows.

-   -   Phase A: A period after phase C when a DL burst is not        discovered (e.g., in a method according to various embodiments        of the present disclosure) and/or after the DL burst is        discovered.    -   Phase B: In the case where a DL burst is discovered (e.g., in a        method according to various embodiments of the present        disclosure), a PDCCH monitoring occasion is included in the        starting k slot(s) of the DL burst. Herein, k may be preset to a        specific value (e.g., k=1) or configured by higher-layer        signaling such as RRC/MAC signaling.    -   Phase C: In the case a DL burst is discovered (e.g., in a method        according to various embodiments of the present disclosure), a        PDCCH monitoring occasion is not included in the starting k        slot(s) of the DL burst. Herein, k may be preset to a specific        value (e.g., k=1) or configured by higher-layer signaling such        as RRC/MAC signaling.

For example, switching between phases may be signalled by at least oneof the following options.

-   -   Opt 1: Explicitly signalled by specific DCI    -   Opt 2: Implicitly signalled by information indicating time-axis        channel occupancy of the BS in DCI

For example, in Opt 1, the BS may indicate to the UE whether a slotcarrying DCI (and/or the following n slot(s)) belongs to phase B/phase Cby using a specific field (e.g., a new field indicating a phase) in theDCI and/or at least some state of an existing field in the DCI.

For example, in Opt 2, when the UE recognizes the corresponding slot asa duration belonging to phase B from the DCI indicating time-axischannel occupancy of the BS, the UE may perform PDCCH monitoringcorresponding to phase B in the slot. For example, in Opt 2, when the UErecognizes the corresponding slot as a period belonging to phase C fromthe DCI indicating time-axis channel occupancy of the BS, the UE mayperform PDCCH monitoring corresponding to phase C in the slot.

In an exemplary embodiment, considering that the UE triggers a new PDCCHmonitoring behaviour in each switching between phases, a time delaycaused by a processing time of the UE may be considered.

For example, it is assumed that a time delay of X symbol(s) is taken forswitching from phase A to phase B.

Based on the assumption, for example, it may be regulated that when theUE recognizes that phase B starts from symbol #Y, a PDCCH monitoringbehaviour corresponding to phase B is actually applied, starting fromsymbol #(X+Y).

For example, X may be a UE capability value. For example, X may be setto a different value according to a UE capability.

For example, the UE may report a UE capability value (e.g., informationabout the UE's capability) to the BS, and the BS may configure an Xvalue for the UE based on the reported capability value by higher-layersignalling such as RRC signalling.

For example, a per-phase monitoring time pattern may be defined for eachsearch space (and/or CORESET and/or DCI format and/or RNTI).

For example, the monitoring time pattern may include all or a part of atleast the following parameters.

-   -   monitoringSlotPeriodicityAndOffset: This parameter may be        related to information about PDCCH monitoring slot(s) configured        by a periodicity and an offset. For example, if the value of the        parameter is sl1, the UE may monitor a search space in each        slot. For example, if the value of the parameter is sl4, the UE        may monitor a search space in every fourth slot.    -   monitoringSymbolsWithinSlot: This parameter may be related to        information about the first symbol(s) for PDCCH monitoring in        slot(s) configured for PDCCH monitoring. For example, if the        value of the parameter is 1000000000000, the UE may start        searching in the first symbol of a slot. For example, if the        value of the parameter is 0100000000000, the UE may start        searching in the second symbol of the slot.

In another example, a different number of per-AL PDCCH blind decoding(BD) candidates and/or a different search space type and/or a differentDCI format may be configured for each search space.

Referring to FIG. 26 , a time pattern configuration for each searchspace set may be given as follows.

-   -   Search space set #0        -   Phase A/B: PDCCH monitoring in each slot, and a CORESET            duration starts in symbol #0/4/7/11        -   Phase C: PDCCH monitoring in each slot, and a CORESET            duration starts in symbol #0    -   Search space set #1        -   Phase A/B: Monitoring off. That is, monitoring may not be            performed.        -   Phase C: PDCCH monitoring in each slot, and a CORESET            duration starts in symbol #0    -   Search space set #2        -   Phase A/B: Monitoring off. That is, monitoring may not be            performed.        -   Phase C: PDCCH monitoring in each slot, and a CORESET            duration starts in symbol #0/4/7/11

3.3. Cross-Carrier Scheduling (CCS) Method

FIG. 28 is a diagram illustrating an exemplary scheduling methodaccording to various embodiments of the present disclosure.

Referring to FIG. 28 , in operation 2801 according to an exemplaryembodiment, a BS may perform a DL CAP for a plurality of cells (e.g.,cells included in a specific cell group) to transmit schedulinginformation to a UE. For example, the DL CAP for the plurality of cellsmay be one or more of the afore-described various DL CAPs for DLtransmission.

In operation 2803 according to an exemplary embodiment, the BS maytransmit scheduling information for one or more cells to the UEaccording to the result of the DL CAP.

For example, when the BS succeeds in the DL CAP only for some cell(s) ofthe plurality of cells, the BS may transmit scheduling information forone or more of the plurality of cells (i.e., one or more cells among theplurality of cells) on one or more of the some cell(s) (i.e., on one ormore cells among the some cell(s)). For example, in case 1 which will bedescribed later, the BS may transmit scheduling information for acorresponding cell (and/or one or more of cells in which the DL CAP isfailed) on a specific cell (in which the DL CAP is successful).

In another example, when the BS succeeds in the DL CAP for all of theplurality of cells, the BS may transmit scheduling information for oneor more of the plurality of cells to the UE on the one or more of theplurality of cells. For example, as in case 2 which will be describedlater, the BS may transmit scheduling information for each cell on thecell to the UE (SCS) or scheduling information for a corresponding cell(and one or more other cells than the corresponding cell) on a specificone of the plurality of cells.

In operation 2805 according to an exemplary embodiment, the UE mayperform a signal transmission/reception scheduled for one or more cellsbased on scheduling information (e.g., DCI) for the one or more cells,received from the BS. For example, when the UE is to transmit a specificsignal on a specific cell (and/or a plurality of cells including thespecific cell) to the BS, the UE may transmit the signal to the BS basedon the result of a UL CAP for the specific cell (and/or the plurality ofcells including the specific cell). For example, the UL CAP for thespecific cell (and/or the plurality of cells including the specificcell) may be one or more of the afore-described UL CAPs for ULtransmission.

Now, a description will be given of a specific operation of a UE and/ora BS in a scheduling method according to various embodiments of thepresent disclosure.

In the LTE and NR systems, for example, CCS may be configured, in whicha scheduling cell and a scheduled cell are different. The motivation ofintroducing CCS is that the probability of succeeding in DCI receptionmay be higher on a scheduling cell than on a scheduled cell.

In addition, for example, since a scheduling cell in which the BS willsucceed in a CAP may not be predicted, a plurality of scheduling cellsmay be configured for a single scheduled cell in the NR system using anunlicensed band.

Hereinbelow, various embodiments of the present disclosure may berelated to a CCS method for increasing the CAP success probability of ascheduling cell. In this subclause and various embodiments of thepresent disclosure, a cell may be replaced with a BWP and/or an activeBWP and/or a channel and/or a CAP (LBT) subband (in the cell).

3.3.1. Operation of Receiver Side (Entity A)

3.3.1.1. [Method #3-1A] Any-To-Any CCS Method

According to various embodiments of the present disclosure, a specificcell group may be defined and any of the cells of the cell group isallowed to be scheduled.

For example, it is assumed that cell #1 and cell #2 are grouped into theabove-described (CCS) cell group.

Based on the assumption, for example:

-   -   Case 1: When a CAP (LBT) is successful only in one of the two        cells, the cell may schedule one and/or both of the cells. For        example, when the CAP is successful in cell #1, cell #1 may        schedule both cell #1 and cell #2 or only one of cell #1 and        cell #2.    -   Case 2: When the CAP (LBT) is successful in both cells, each        cell may schedule itself or a specific one of the two cells may        schedule both of the cells and/or a specific one of the cells.        For example, when the CAP is successful in both of cell #1 and        cell #2, cell #1 and/or cell #2 may schedule itself (SCS), or        cell #1 may schedule both or one of cell #1 and cell #2.

In another example, it is assumed that cell #1, cell #2 and cell #3 aregrouped into a cell group.

Based on the assumption, for example:

-   -   Case 1: When a CAP (LBT) is successful only in one of the three        cells, the cell may schedule one or more and/or all of the        cells. For example, when the CAP is successful only in cell #1,        cell #1 may schedule all of cell #1, cell #2, and cell #3 or one        or more of cell #1, cell #2, and cell #3.    -   Case 2: When the CAP (LBT) is successful in all of the three        cells, each cell may schedule itself or a specific one of the        three cells may schedule two cells and/or specific one or more        of the cells. For example, when the CAP is successful in all of        cell #1, cell #2, and cell #3, cell #1 and/or cell #2 and/or        cell #3 may schedule itself (SCS), or cell #1 may schedule all        of cell #1, cell #2, and cell #3 or one or more of cell #1, cell        #2, and cell #3.

In an exemplary embodiment, the same CORESET configuration and/or thesame search space set configuration may be set for the cells of a cellgroup.

For example, (an index is assigned to each cell of the cell group), aCORESET configuration and/or a search space set configuration set forthe cell with the lowest index (or the highest index) may be applied toall cells of the group.

In an exemplary embodiment, to match a DCI size for CCS to a DCI sizefor SCS, a CIF may also be present in DCI in the case of SCS (like CCS).

For example, it is assumed that five cells belong to a cell group andunique cell indexes are assigned to the cells. Based on the assumption,for example, a 3-bit CIF may always exist in DCI irrespective of whichcell of the cell group is scheduled. For example, the cell group may beapplied only for UL scheduling. For example, while DL scheduling DCI mayconfigure SCS and/or CCS, UL grant DCI may always support CCS.

The above-described various embodiments of the present disclosure may beapplied in the same manner to a DCI format (referred to as DCI format 3,for the convenience of description) carrying COT information (e.g.,time-axis and/or frequency-axis information about a corresponding COT)as well as scheduling DCI.

For example, a cell group sharing COT information may be defined. Forexample, COT information about all carriers (cells) of the group may bedelivered in DCI format 3 transmitted on any cell (or a specificpredefined cell) of the cell group.

For example, DCI format 3 may be transmitted on a GC-PDCCH. That is, DCIformat 3 may include group-common information.

For example, one DCI format 3 may deliver COT information about aplurality of UEs and/or cells. In this case, for example, a cellcarrying the COT information may be pre-signaled in some field for eachUE.

In another example, it may be regulated that COT informationcorresponding to a specific field of DCI format 3 corresponds toinformation about a cell spaced from a common reference point by aspecific offset on the frequency axis.

For example, COT information corresponding to a cell starting at anoffset of 10 RBs from the common reference point may be set in field A,and COT information corresponding to a cell starting at an offset of {10RBs+20 MHz} from the common reference point may be set in field B. Forexample, each UE may acquire COT information in a corresponding fieldbased on frequency-axis resources of each cell configured for the UE.

In the above-described various embodiments of the present disclosure, acell may be replaced with a BWP and/or an active BWP and/or a celland/or a CAP (LBT) subband. For example, the CAP subband is a basic unitfor a CAP, which may have a size of, for example, 20 MHz.

The above-described various embodiments of the present disclosure may beapplied irrespective of whether CCS is configured for a specificunlicensed-band cell. For example, UL grant DCI may always support CCS.For example, whether DL scheduling DCI is SCS and/or CCS may beconfigured by RRC signaling or the like.

3.3.1.2. [Method #3-2A] Configuration of PDCCH Monitoring Occasion forDCI Format Carrying COT Information

Referring to FIG. 24 again, for example, in the NR system, a PDCCHmonitoring occasion for a search space set configured for a scheduledcell (and/or an active BWP in the cell, which may be replaced with a BWPand/or an active BWP and/or a cell and/or a CAP (LBT) subband in thissubclause and various embodiments of the present disclosure) may belinked to a search space set for a scheduling cell with the same indexas the search space cell of the scheduled cell, and PDCCH monitoring isperformed in the PDCCH monitoring occasion.

However, a search space set associated with a DCI format (referred to asDCI format 3, for the convenience) carrying COT information (e.g.,time-axis and/or frequency-axis information about a corresponding COT)may need separate handling. For example, because the UE may determinewhether a DL Tx burst starts in an unlicensed band based on thecorresponding DCI format 3, it may be favorable to separately handle thecorresponding DCI format 3.

For example, for a search space set associated with DCI format, CIformat 3 may be monitored in a PDCCH monitoring occasion configured in a(still) scheduled cell, not a scheduling cell.

For example, when multiple DCI formats including DCI format 3 are linkedto a corresponding search space set, at least one of the followingoptions may be performed.

-   -   Opt 1: It is regulated that monitoring for all DCI formats        linked to the search space set is based on a configuration on        the scheduled cell, or    -   Opt 2: It is regulated that monitoring of DCI format 3 among the        DCI formats linked to the search space set is based on a        configuration on the scheduled cell and the other DCI format(s)        is monitored based on a configuration on the scheduling cell.

3.3.1.3. [Method #3-3A] Scheduling Restriction for CCS Configuration

For example, if the BS is to transmit a signal on a scheduled cell aftertransmitting DCI (a scheduling DL signal/channel) on a scheduling celland fails in a CAP for the scheduled cell, the UE which has received thetransmitted DCI may unnecessarily attempt to receive a DLsignal/channel. According to various embodiments of the presentdisclosure, at least one of the following options may be performed toprevent this unnecessary UE operation.

-   -   Opt 1: The UE may not receive DCI scheduling a scheduled cell or        may not expect the DCI before a PDCCH monitoring occasion in a        search space set configured in the scheduling cell starting (or        ending) earlier than a DL COT starting time on the scheduled        cell.    -   Opt 2: The UE may not receive, on a scheduling cell, DCI        scheduling a DL signal/channel starting (or ending) earlier than        a DL COT starting time on a scheduled cell, or may not expect to        receive the DCI on the scheduling cell.

3.3.2. Operation of Transmitter Side (Entity B)

3.3.2.1. [Method #3-1B] Any-to-Any CCS Method

According to various embodiments of the present disclosure, a specificcell group may be defined and any of the cells of the cell group isallowed to be scheduled.

For example, it is assumed that cell #1 and cell #2 are grouped into theabove-described (CCS) cell group.

Based on the assumption, for example:

-   -   Case 1: When a CAP (LBT) is successful only in one of the two        cells, the cell may schedule one and/or both of the cells. For        example, when the CAP is successful only in cell #1, cell #1 may        schedule both cell #1 and cell #2 or only one of cell #1 and        cell #2.    -   Case 2: When the CAP (LBT) is successful in both cells, each        cell may schedule itself or a specific one of the two cells may        schedule both of the cells and/or a specific one of the cells.        For example, when the CAP is successful in both of cell #1 and        cell #2, cell #1 and/or cell #2 may schedule itself (SCS), or        cell #1 may schedule both or one of cell #1 and cell #2.

In another example, it is assumed that cell #1, cell #2 and cell #3 aregrouped into a cell group.

On the assumption, for example:

-   -   Case 1: When a CAP (LBT) is successful only in one of the three        cells, the cell may schedule one or more and/or all of the        cells. For example, when the CAP is successful only in cell #1,        cell #1 may schedule all of cell #1, cell #2, and cell #3 or one        or more of cell #1, cell #2, and cell #3.    -   Case 2: When the CAP (LBT) is successful in all of the three        cells, each cell may schedule itself or a specific one of the        three cells may schedule two cells and/or specific one or more        of the cells. For example, when the CAP is successful in all of        cell #1, cell #2, and cell #3, cell #1 and/or cell #2 and/or        cell #3 may schedule itself (SCS), or cell #1 may schedule all        of cell #1, cell #2, and cell #3 or one or more of cell #1, cell        #2, and cell #3.

In an exemplary embodiment, the same CORESET configuration and/or thesame search space set configuration may be set for the cells of a cellgroup.

For example, (an index is assigned to each cell of the cell group), aCORESET configuration and/or a search space set configuration set forthe cell with the lowest index (or the highest index) may be applied toall cells of the group.

In an exemplary embodiment, to match a DCI size for CCS to a DCI sizefor SCS, a CIF may also be present in DCI in the case of SCS (like CCS).

For example, it is assumed that five cells belong to a cell group andunique cell indexes are assigned to the respective cells. Based on theassumption, for example, a 3-bit CIF may always exist in DCIirrespective of which cell of the cell group is scheduled. For example,the cell group may be applied only for UL scheduling. For example, whileDL scheduling DCI may configure SCS and/or CCS, UL grant DCI may alwayssupport CCS.

The above-described various embodiments of the present disclosure may beapplied in the same manner to a DCI format (referred to as DCI format 3,for the convenience of description) carrying COT information (e.g.,time-axis and/or frequency-axis information about a corresponding COT)as well as scheduling DCI.

For example, a cell group sharing COT information may be defined. Forexample, COT information about all carriers (cells) of the group may bedelivered in DCI format 3 transmitted on any cell (or a specificpredefined cell) of the cell group.

For example, DCI format 3 may be transmitted on a GC-PDCCH. That is, DCIformat 3 may include group-common information.

For example, one DCI format 3 may deliver COT information about aplurality of UEs and/or cells. In this case, for example, which fieldcarries COT information about which cell may be pre-signaled for eachUE.

In another example, it may be regulated that COT informationcorresponding to a specific field of DCI format 3 corresponds toinformation about a cell spaced from a common reference point by aspecific offset on the frequency axis.

For example, COT information corresponding to a cell starting at anoffset of 10 RBs from the common reference point may be set in field A,and COT information corresponding to a cell starting at an offset of {10RBs+20 MHz} from the common reference point may be set in field B. Forexample, each UE may acquire COT information in a corresponding fieldbased on frequency-axis resources of the cell configured for the UE.

In the above-described various embodiments of the present disclosure, acell may be replaced with a BWP and/or an active BWP and/or a celland/or a CAP (LBT) subband. For example, the CAP subband is a basic unitfor a CAP, which may have a size of, for example, 20 MHz.

The above-described various embodiments of the present disclosure may beapplied irrespective of whether CCS is configured for a specificunlicensed-band cell. For example, UL grant DCI may always support CCS.For example, whether DL scheduling DCI is SCS and/or CCS may beconfigured by RRC signaling or the like.

3.3.2.2. [Method #3-2B] Configuration of PDCCH Monitoring Occasion forDCI Format Carrying COT Information

Referring to FIG. 24 again, for example, in the NR system, a PDCCHmonitoring occasion for a search space set configured for a scheduledcell (and/or an active BWP in the cell, which may be replaced with a BWPand/or an active BWP and/or a cell and/or a CAP (LBT) subband (in thecell) in this subclause and various embodiments of the presentdisclosure) may be linked to a search space set for a scheduling cell,with the same index as the search space set of the scheduled cell, andPDCCH monitoring is performed in the PDCCH monitoring occasion.

However, a search space set associated with DCI format (referred to asDCI format 3, for the convenience) carrying COT information (e.g.,time-axis and/or frequency-axis information about a corresponding COT)may need separate handling. For example, because the UE may determinewhether a DL Tx burst starts in an unlicensed band based on thecorresponding DCI format 3, it may be favorable to separately handle thecorresponding DCI format 3.

For example, for a search space set associated with DCI format 3, DCIformat 3 may be monitored in a PDCCH monitoring occasion configured in a(still) scheduled cell, not a scheduling cell.

For example, when multiple DCI formats including DCI format 3 are linkedto a corresponding search space set, at least one of the followingoptions may be performed.

-   -   Opt 1: It is regulated that monitoring for all DCI formats        linked to the search space set is based on a configuration on a        scheduled cell, or    -   Opt 2: It is regulated that monitoring of DCI format 3 among the        DCI formats linked to the search space set is based on a        configuration on the scheduled cell and the other DCI format(s)        are monitored based on a configuration on a scheduling cell.

3.3.2.3. [Method #3-3B] Scheduling Restriction when CCS is Configured

For example, if the BS is to transmit a signal on a scheduled cell aftertransmitting DCI (a scheduling DL signal/channel) on a scheduling celland fails in a CAP for the scheduled cell, unnecessary resources may beconsumed for the DCI transmission. According to various embodiments ofthe present disclosure, at least one of the following options may beperformed to prevent this unnecessary resource waste.

-   -   Opt 1: The BS may not transmit DCI that schedules a scheduled        cell before a PDCCH monitoring occasion in a search space set        configured in the scheduling cell starting (or ending) earlier        than a DL COT starting time on the scheduled cell.    -   Opt 2: The BS may not transmit, (on a scheduling cell), DCI that        schedules a DL signal/channel starting (or ending) earlier than        a DL COT starting time on a scheduled cell.

Since examples of the above proposed methods may be included as one ofmethods of implementing the present disclosure, it is apparent that theexamples may be regarded as proposed methods. Further, the foregoingproposed methods may be implemented independently, or some of themethods may be implemented in combination (or merged). Further, it maybe regulated that information indicating whether the proposed methodsare applied (or information about the rules of the proposed methods) isindicated to a UE by a pre-defined signal (or a physical-layer orhigher-layer signal) by an eNB, or is requested to a receiving UE or atransmitting UE by the transmitting UE or the receiving UE.

FIG. 29 is a simplified diagram illustrating a method of operating a UEand a BS according to various embodiments of the present disclosure.

FIG. 30 is a flowchart illustrating a method of operating a UE accordingto various embodiments of the present disclosure.

FIG. 31 is a flowchart illustrating a method of operating a BS accordingto various embodiments of the present disclosure.

Referring to FIGS. 29, 30 and 31 , the BS may transmit information aboutgroups for one or more search space sets related to PDCCH monitoring,and the UE may acquire the information about the groups in operations2901, 3001, and 3101 according to an exemplary embodiment.

In operations 2903, 3003, and 3103 according to an exemplary embodiment,the UE may perform PDCCH monitoring according to a search space setrelated to a second group among the groups, based on the informationabout the groups, and the BS may transmit a PDCCH according to thesearch space set related to the second group among the groups.

For example, after one or more of predetermined conditions aresatisfied: (i) after a predetermined first time, PDCCH monitoring maystart in a search space set related to a first group different from thesecond group among the groups, and (ii) PDCCH monitoring may end in thesearch space set related to the second group.

For example, after one or more of predetermined conditions aresatisfied: (i) after a predetermined first time, PDCCH transmission maystart in the search space set related to the first group different fromthe second group among the groups, and (ii) PDCCH transmission may endin the search space set related to the second group.

A more specific operation of a BS and/or a UE according to variousembodiments of the present disclosure may be described and performedbased on the afore-described clause 1 to clause 3.

Since examples of the above-described proposal method may also beincluded in one of implementation methods of the various embodiments ofthe present disclosure, it is obvious that the examples are regarded asa sort of proposed methods. Although the above-proposed methods may beindependently implemented, the proposed methods may be implemented in acombined (aggregated) form of a part of the proposed methods. A rule maybe defined such that the BS informs the UE of information as to whetherthe proposed methods are applied (or information about rules of theproposed methods) through a predefined signal (e.g., a physical layersignal or a higher-layer signal).

4. Exemplary Configurations of Devices Implementing Various Embodimentsof the Present Disclosure

4.1. Exemplary Configurations of Devices to which Various Embodiments ofthe Present Disclosure are Applied

FIG. 32 is a diagram illustrating devices that implement variousembodiments of the present disclosure.

The devices illustrated in FIG. 32 may be a UE and/or a BS (e.g., eNB orgNB) adapted to perform the afore-described mechanisms, or any devicesperforming the same operation.

Referring to FIG. 32 , the device may include a digital signal processor(DSP)/microprocessor 210 and a radio frequency (RF) module (transceiver)235. The DSP/microprocessor 210 is electrically coupled to thetransceiver 235 and controls the transceiver 235. The device may furtherinclude a power management module 205, a battery 255, a display 215, akeypad 220, a SIM card 225, a memory device 230, an antenna 240, aspeaker 245, and an input device 250, depending on a designer'sselection.

Particularly, FIG. 32 may illustrate a UE including a receiver 235configured to receive a request message from a network and a transmitter235 configured to transmit timing transmission/reception timinginformation to the network. These receiver and transmitter may form thetransceiver 235. The UE may further include a processor 210 coupled tothe transceiver 235.

Further, FIG. 32 may illustrate a network device including a transmitter235 configured to transmit a request message to a UE and a receiver 235configured to receive timing transmission/reception timing informationfrom the UE. These transmitter and receiver may form the transceiver235. The network may further include the processor 210 coupled to thetransceiver 235. The processor 210 may calculate latency based on thetransmission/reception timing information.

A processor included in a UE (or a communication device included in theUE) and a BE (or a communication device included in the BS) according tovarious embodiments of the present disclosure may operate as follows,while controlling a memory.

According to various embodiments of the present disclosure, a UE or a BSmay include at least one transceiver, at least one memory, and at leastone processor coupled to the at least one transceiver and the at leastone memory. The at least one memory may store instructions causing theat least one processor to perform the following operations.

A communication device included in the UE or the BS may be configured toinclude the at least one processor and the at least one memory. Thecommunication device may be configured to include the at least onetransceiver, or may be configured not to include the at least onetransceiver but to be connected to the at least one transceiver.

According to various embodiments of the present disclosure, at least oneprocessor included in a UE (or at least one processor of a communicationdevice in the UE) may acquire information about groups for one or moresearch space sets related to physical downlink control channel (PDCCH)monitoring. According to various embodiments of the present disclosure,the at least one processor included in the UE may perform the PDCCHmonitoring according to a search space set related to a second groupamong the groups, based on the information about the groups. Forexample, after one or more of predetermined conditions are satisfied:(i) after a first predetermined time, PDCCH monitoring may startaccording to a search space set related to a first group different fromthe second group among the groups, and (ii) the PDCCH monitoring may endaccording to the search space set related to the second group.

According to various embodiments of the present disclosure, at least oneprocessor included in a BS (or at least one processor of a communicationdevice in the BS) may transmit information about groups for one or moresearch space sets related to PDCCH monitoring. According to variousembodiments of the present disclosure, the at least one processorincluded in the BS may transmit a PDCCH according to a search space setrelated to a second group among the groups. According to variousembodiments of the present disclosure, after one or more ofpredetermined conditions are satisfied: (i) after a first predeterminedtime, PDCCH transmission may start according to a search space setrelated to a first group different from the second group among thegroups, and (ii) the PDCCH transmission may end according to the searchspace set related to the second group.

A more specific operation of a processor included in a BS and/or a UEaccording to various embodiments of the present disclosure may bedescribed and performed based on the afore-described clause 1 to clause3.

Unless contradicting with each other, various embodiments of the presentdisclosure may be implemented in combination. For example, the BS and/orthe UE according to various embodiments of the present disclosure mayperform operations in combination of the embodiments of theafore-described clause 1 to clause 3, unless contradicting with eachother.

4.2. Example of Communication System to which Various Embodiments of thePresent Disclosure are Applied

In the present specification, various embodiments of the presentdisclosure have been mainly described in relation to data transmissionand reception between a BS and a UE in a wireless communication system.However, various embodiments of the present disclosure are not limitedthereto. For example, various embodiments of the present disclosure mayalso relate to the following technical configurations.

The various descriptions, functions, procedures, proposals, methods,and/or operational flowcharts of the various embodiments of the presentdisclosure described in this document may be applied to, without beinglimited to, a variety of fields requiring wirelesscommunication/connection (e.g., 5G) between devices.

Hereinafter, a description will be given in more detail with referenceto the drawings. In the following drawings/description, the samereference symbols may denote the same or corresponding hardware blocks,software blocks, or functional blocks unless described otherwise.

FIG. 33 illustrates an exemplary communication system to which variousembodiments of the present disclosure are applied.

Referring to FIG. 33 , a communication system 1 applied to the variousembodiments of the present disclosure includes wireless devices, BaseStations (BSs), and a network. Herein, the wireless devices representdevices performing communication using Radio Access Technology (RAT)(e.g., 5G New RAT (NR)) or Long-Term Evolution (LTE)) and may bereferred to as communication/radio/5G devices. The wireless devices mayinclude, without being limited to, a robot 100 a, vehicles 100 b-1 and100 b-2, an eXtended Reality (XR) device 100 c, a hand-held device 100d, a home appliance 100 e, an Internet of Things (IoT) device 100 f, andan Artificial Intelligence (AI) device/server 400. For example, thevehicles may include a vehicle having a wireless communication function,an autonomous driving vehicle, and a vehicle capable of performingcommunication between vehicles. Herein, the vehicles may include anUnmanned Aerial Vehicle (UAV) (e.g., a drone). The XR device may includean Augmented Reality (AR)/Virtual Reality (VR)/Mixed Reality (MR) deviceand may be implemented in the form of a Head-Mounted Device (HMD), aHead-Up Display (HUD) mounted in a vehicle, a television, a smartphone,a computer, a wearable device, a home appliance device, a digitalsignage, a vehicle, a robot, etc. The hand-held device may include asmartphone, a smartpad, a wearable device (e.g., a smartwatch or asmartglasses), and a computer (e.g., a notebook). The home appliance mayinclude a TV, a refrigerator, and a washing machine. The IoT device mayinclude a sensor and a smartmeter. For example, the BSs and the networkmay be implemented as wireless devices and a specific wireless device200 a may operate as a BS/network node with respect to other wirelessdevices.

The wireless devices 100 a to 100 f may be connected to the network 300via the BSs 200. An AI technology may be applied to the wireless devices100 a to 100 f and the wireless devices 100 a to 100 f may be connectedto the AI server 400 via the network 300. The network 300 may beconfigured using a 3G network, a 4G (e.g., LTE) network, or a 5G (e.g.,NR) network. Although the wireless devices 100 a to 100 f maycommunicate with each other through the BSs 200/network 300, thewireless devices 100 a to 100 f may perform direct communication (e.g.,sidelink communication) with each other without passing through theBSs/network. For example, the vehicles 100 b-1 and 100 b-2 may performdirect communication (e.g. Vehicle-to-Vehicle(V2V)/Vehicle-to-everything (V2X) communication). The IoT device (e.g.,a sensor) may perform direct communication with other IoT devices (e.g.,sensors) or other wireless devices 100 a to 100 f.

Wireless communication/connections 150 a, 150 b, or 150 c may beestablished between the wireless devices 100 a to 100 f/BS 200, or BS200/BS 200. Herein, the wireless communication/connections may beestablished through various RATs (e.g., 5G NR) such as uplink/downlinkcommunication 150 a, sidelink communication 150 b (or, D2Dcommunication), or inter BS communication (e.g. relay, Integrated AccessBackhaul (IAB)). The wireless devices and the BSs/the wireless devicesmay transmit/receive radio signals to/from each other through thewireless communication/connections 150 a and 150 b. For example, thewireless communication/connections 150 a and 150 b may transmit/receivesignals through various physical channels. To this end, at least a partof various configuration information configuring processes, varioussignal processing processes (e.g., channel encoding/decoding,modulation/demodulation, and resource mapping/demapping), and resourceallocating processes, for transmitting/receiving radio signals, may beperformed based on the various proposals of the various embodiments ofthe present disclosure.

4.2.1 Example of Wireless Devices to which Various Embodiments of thePresent Disclosure are Applied

FIG. 34 illustrates exemplary wireless devices to which variousembodiments of the present disclosure are applicable.

Referring to FIG. 34 , a first wireless device 100 and a second wirelessdevice 200 may transmit radio signals through a variety of RATs (e.g.,LTE and NR). Herein, {the first wireless device 100 and the secondwireless device 200} may correspond to {the wireless device 100 x andthe BS 200} and/or {the wireless device 100 x and the wireless device100 x} of FIG. W1 .

The first wireless device 100 may include one or more processors 102 andone or more memories 104 and additionally further include one or moretransceivers 106 and/or one or more antennas 108. The processor(s) 102may control the memory(s) 104 and/or the transceiver(s) 106 and may beconfigured to implement the descriptions, functions, procedures,proposals, methods, and/or operational flowcharts disclosed in thisdocument. For example, the processor(s) 102 may process informationwithin the memory(s) 104 to generate first information/signals and thentransmit radio signals including the first information/signals throughthe transceiver(s) 106. The processor(s) 102 may receive radio signalsincluding second information/signals through the transceiver 106 andthen store information obtained by processing the secondinformation/signals in the memory(s) 104. The memory(s) 104 may beconnected to the processor(s) 102 and may store a variety of informationrelated to operations of the processor(s) 102. For example, thememory(s) 104 may store software code including commands for performinga part or the entirety of processes controlled by the processor(s) 102or for performing the descriptions, functions, procedures, proposals,methods, and/or operational flowcharts disclosed in this document.Herein, the processor(s) 102 and the memory(s) 104 may be a part of acommunication modem/circuit/chip designed to implement RAT (e.g., LTE orNR). The transceiver(s) 106 may be connected to the processor(s) 102 andtransmit and/or receive radio signals through one or more antennas 108.Each of the transceiver(s) 106 may include a transmitter and/or areceiver. The transceiver(s) 106 may be interchangeably used with RadioFrequency (RF) unit(s). In the various embodiments of the presentdisclosure, the wireless device may represent a communicationmodem/circuit/chip.

The second wireless device 200 may include one or more processors 202and one or more memories 204 and additionally further include one ormore transceivers 206 and/or one or more antennas 208. The processor(s)202 may control the memory(s) 204 and/or the transceiver(s) 206 and maybe configured to implement the descriptions, functions, procedures,proposals, methods, and/or operational flowcharts disclosed in thisdocument. For example, the processor(s) 202 may process informationwithin the memory(s) 204 to generate third information/signals and thentransmit radio signals including the third information/signals throughthe transceiver(s) 206. The processor(s) 202 may receive radio signalsincluding fourth information/signals through the transceiver(s) 106 andthen store information obtained by processing the fourthinformation/signals in the memory(s) 204. The memory(s) 204 may beconnected to the processor(s) 202 and may store a variety of informationrelated to operations of the processor(s) 202. For example, thememory(s) 204 may store software code including commands for performinga part or the entirety of processes controlled by the processor(s) 202or for performing the descriptions, functions, procedures, proposals,methods, and/or operational flowcharts disclosed in this document.Herein, the processor(s) 202 and the memory(s) 204 may be a part of acommunication modem/circuit/chip designed to implement RAT (e.g., LTE orNR). The transceiver(s) 206 may be connected to the processor(s) 202 andtransmit and/or receive radio signals through one or more antennas 208.Each of the transceiver(s) 206 may include a transmitter and/or areceiver. The transceiver(s) 206 may be interchangeably used with RFunit(s). In the various embodiments of the present disclosure, thewireless device may represent a communication modem/circuit/chip.

Hereinafter, hardware elements of the wireless devices 100 and 200 willbe described more specifically. One or more protocol layers may beimplemented by, without being limited to, one or more processors 102 and202. For example, the one or more processors 102 and 202 may implementone or more layers (e.g., functional layers such as PHY, MAC, RLC, PDCP,RRC, and SDAP). The one or more processors 102 and 202 may generate oneor more Protocol Data Units (PDUs) and/or one or more Service Data Unit(SDUs) according to the descriptions, functions, procedures, proposals,methods, and/or operational flowcharts disclosed in this document. Theone or more processors 102 and 202 may generate messages, controlinformation, data, or information according to the descriptions,functions, procedures, proposals, methods, and/or operational flowchartsdisclosed in this document. The one or more processors 102 and 202 maygenerate signals (e.g., baseband signals) including PDUs, SDUs,messages, control information, data, or information according to thedescriptions, functions, procedures, proposals, methods, and/oroperational flowcharts disclosed in this document and provide thegenerated signals to the one or more transceivers 106 and 206. The oneor more processors 102 and 202 may receive the signals (e.g., basebandsignals) from the one or more transceivers 106 and 206 and acquire thePDUs, SDUs, messages, control information, data, or informationaccording to the descriptions, functions, procedures, proposals,methods, and/or operational flowcharts disclosed in this document.

The one or more processors 102 and 202 may be referred to ascontrollers, microcontrollers, microprocessors, or microcomputers. Theone or more processors 102 and 202 may be implemented by hardware,firmware, software, or a combination thereof. As an example, one or moreApplication Specific Integrated Circuits (ASICs), one or more DigitalSignal Processors (DSPs), one or more Digital Signal Processing Devices(DSPDs), one or more Programmable Logic Devices (PLDs), or one or moreField Programmable Gate Arrays (FPGAs) may be included in the one ormore processors 102 and 202. The descriptions, functions, procedures,proposals, methods, and/or operational flowcharts disclosed in thisdocument may be implemented using firmware or software and the firmwareor software may be configured to include the modules, procedures, orfunctions. Firmware or software configured to perform the descriptions,functions, procedures, proposals, methods, and/or operational flowchartsdisclosed in this document may be included in the one or more processors102 and 202 or stored in the one or more memories 104 and 204 so as tobe driven by the one or more processors 102 and 202. The descriptions,functions, procedures, proposals, methods, and/or operational flowchartsdisclosed in this document may be implemented using firmware or softwarein the form of code, commands, and/or a set of commands.

The one or more memories 104 and 204 may be connected to the one or moreprocessors 102 and 202 and store various types of data, signals,messages, information, programs, code, instructions, and/or commands.The one or more memories 104 and 204 may be configured by Read-OnlyMemories (ROMs), Random Access Memories (RAMs), Electrically ErasableProgrammable Read-Only Memories (EPROMs), flash memories, hard drives,registers, cash memories, computer-readable storage media, and/orcombinations thereof. The one or more memories 104 and 204 may belocated at the interior and/or exterior of the one or more processors102 and 202. The one or more memories 104 and 204 may be connected tothe one or more processors 102 and 202 through various technologies suchas wired or wireless connection.

The one or more transceivers 106 and 206 may transmit user data, controlinformation, and/or radio signals/channels, mentioned in the methodsand/or operational flowcharts of this document, to one or more otherdevices. The one or more transceivers 106 and 206 may receive user data,control information, and/or radio signals/channels, mentioned in thedescriptions, functions, procedures, proposals, methods, and/oroperational flowcharts disclosed in this document, from one or moreother devices. For example, the one or more transceivers 106 and 206 maybe connected to the one or more processors 102 and 202 and transmit andreceive radio signals. For example, the one or more processors 102 and202 may perform control so that the one or more transceivers 106 and 206may transmit user data, control information, or radio signals to one ormore other devices. The one or more processors 102 and 202 may performcontrol so that the one or more transceivers 106 and 206 may receiveuser data, control information, or radio signals from one or more otherdevices. The one or more transceivers 106 and 206 may be connected tothe one or more antennas 108 and 208 and the one or more transceivers106 and 206 may be configured to transmit and receive user data, controlinformation, and/or radio signals/channels, mentioned in thedescriptions, functions, procedures, proposals, methods, and/oroperational flowcharts disclosed in this document, through the one ormore antennas 108 and 208. In this document, the one or more antennasmay be a plurality of physical antennas or a plurality of logicalantennas (e.g., antenna ports). The one or more transceivers 106 and 206may convert received radio signals/channels etc. from RF band signalsinto baseband signals in order to process received user data, controlinformation, radio signals/channels, etc. using the one or moreprocessors 102 and 202. The one or more transceivers 106 and 206 mayconvert the user data, control information, radio signals/channels, etc.processed using the one or more processors 102 and 202 from the baseband signals into the RF band signals. To this end, the one or moretransceivers 106 and 206 may include (analog) oscillators and/orfilters.

According to various embodiments of the present disclosure, one or morememories (e.g., 104 or 204) may store instructions or programs which,when executed, cause one or more processors operably coupled to the oneor more memories to perform operations according to various embodimentsor implementations of the present disclosure.

According to various embodiments of the present disclosure, acomputer-readable storage medium may store one or more instructions orcomputer programs which, when executed by one or more processors, causethe one or more processors to perform operations according to variousembodiments or implementations of the present disclosure.

According to various embodiments of the present disclosure, a processingdevice or apparatus may include one or more processors and one or morecomputer memories connected to the one or more processors. The one ormore computer memories may store instructions or programs which, whenexecuted, cause the one or more processors operably coupled to the oneor more memories to perform operations according to various embodimentsor implementations of the present disclosure.

4.2.2. Example of Using Wireless Devices to which Various Embodiments ofthe Present Disclosure are Applied

FIG. 35 illustrates other exemplary wireless devices to which variousembodiments of the present disclosure are applied. The wireless devicesmay be implemented in various forms according to a use case/service (seeFIG. 33 ).

Referring to FIG. 35 , wireless devices 100 and 200 may correspond tothe wireless devices 100 and 200 of FIG. 33 and may be configured byvarious elements, components, units/portions, and/or modules. Forexample, each of the wireless devices 100 and 200 may include acommunication unit 110, a control unit 120, a memory unit 130, andadditional components 140. The communication unit may include acommunication circuit 112 and transceiver(s) 114. For example, thecommunication circuit 112 may include the one or more processors 102 and202 and/or the one or more memories 104 and 204 of FIG. 33 . Forexample, the transceiver(s) 114 may include the one or more transceivers106 and 206 and/or the one or more antennas 108 and 208 of FIG. 33 . Thecontrol unit 120 is electrically connected to the communication unit110, the memory 130, and the additional components 140 and controlsoverall operation of the wireless devices. For example, the control unit120 may control an electric/mechanical operation of the wireless devicebased on programs/code/commands/information stored in the memory unit130. The control unit 120 may transmit the information stored in thememory unit 130 to the exterior (e.g., other communication devices) viathe communication unit 110 through a wireless/wired interface or store,in the memory unit 130, information received through the wireless/wiredinterface from the exterior (e.g., other communication devices) via thecommunication unit 110.

The additional components 140 may be variously configured according totypes of wireless devices. For example, the additional components 140may include at least one of a power unit/battery, input/output (I/O)unit, a driving unit, and a computing unit. The wireless device may beimplemented in the form of, without being limited to, the robot (100 aof FIG. W1 ), the vehicles (100 b-1 and 100 b-2 of FIG. W1 ), the XRdevice (100 c of FIG. W1 ), the hand-held device (100 d of FIG. W1 ),the home appliance (100 e of FIG. W1 ), the IoT device (100 f of FIG. W1), a digital broadcast terminal, a hologram device, a public safetydevice, an MTC device, a medicine device, a fintech device (or a financedevice), a security device, a climate/environment device, the AIserver/device (400 of FIG. W1 ), the BSs (200 of FIG. W1 ), a networknode, etc. The wireless device may be used in a mobile or fixed placeaccording to a use-example/service.

In FIG. 35 , the entirety of the various elements, components,units/portions, and/or modules in the wireless devices 100 and 200 maybe connected to each other through a wired interface or at least a partthereof may be wirelessly connected through the communication unit 110.For example, in each of the wireless devices 100 and 200, the controlunit 120 and the communication unit 110 may be connected by wire and thecontrol unit 120 and first units (e.g., 130 and 140) may be wirelesslyconnected through the communication unit 110. Each element, component,unit/portion, and/or module within the wireless devices 100 and 200 mayfurther include one or more elements. For example, the control unit 120may be configured by a set of one or more processors. As an example, thecontrol unit 120 may be configured by a set of a communication controlprocessor, an application processor, an Electronic Control Unit (ECU), agraphical processing unit, and a memory control processor. As anotherexample, the memory 130 may be configured by a Random Access Memory(RAM), a Dynamic RAM (DRAM), a Read Only Memory (ROM)), a flash memory,a volatile memory, a non-volatile memory, and/or a combination thereof.

Hereinafter, an example of implementing FIG. 35 will be described indetail with reference to the drawings.

4.2.3. Example of Portable Device to which Various Embodiments of thePresent Disclosure are Applied

FIG. 36 illustrates an exemplary portable device to which variousembodiments of the present disclosure are applied. The portable devicemay be any of a smartphone, a smartpad, a wearable device (e.g., asmartwatch or smart glasses), and a portable computer (e.g., a laptop).A portable device may also be referred to as mobile station (MS), userterminal (UT), mobile subscriber station (MSS), subscriber station (SS),advanced mobile station (AMS), or wireless terminal (WT).

Referring to FIG. 36 , a hand-held device 100 may include an antennaunit 108, a communication unit 110, a control unit 120, a memory unit130, a power supply unit 140 a, an interface unit 140 b, and an I/O unit140 c. The antenna unit 108 may be configured as a part of thecommunication unit 110. Blocks 110 to 130/140 a to 140 c correspond tothe blocks 110 to 130/140 of FIG. X3 , respectively.

The communication unit 110 may transmit and receive signals (e.g., dataand control signals) to and from other wireless devices or BSs. Thecontrol unit 120 may perform various operations by controllingconstituent elements of the hand-held device 100. The control unit 120may include an Application Processor (AP). The memory unit 130 may storedata/parameters/programs/code/commands needed to drive the hand-helddevice 100. The memory unit 130 may store input/output data/information.The power supply unit 140 a may supply power to the hand-held device 100and include a wired/wireless charging circuit, a battery, etc. Theinterface unit 140 b may support connection of the hand-held device 100to other external devices. The interface unit 140 b may include variousports (e.g., an audio I/O port and a video I/O port) for connection withexternal devices. The I/O unit 140 c may input or output videoinformation/signals, audio information/signals, data, and/or informationinput by a user. The I/O unit 140 c may include a camera, a microphone,a user input unit, a display unit 140 d, a speaker, and/or a hapticmodule.

As an example, in the case of data communication, the I/O unit 140 c mayacquire information/signals (e.g., touch, text, voice, images, or video)input by a user and the acquired information/signals may be stored inthe memory unit 130. The communication unit 110 may convert theinformation/signals stored in the memory into radio signals and transmitthe converted radio signals to other wireless devices directly or to aBS. The communication unit 110 may receive radio signals from otherwireless devices or the BS and then restore the received radio signalsinto original information/signals. The restored information/signals maybe stored in the memory unit 130 and may be output as various types(e.g., text, voice, images, video, or haptic) through the I/O unit 140c.

4.2.4. Example of Vehicle or Autonomous Driving Vehicle to which VariousEmbodiments of the Present Disclosure.

FIG. 37 illustrates an exemplary vehicle or autonomous driving vehicleto which various embodiments of the present disclosure. The vehicle orautonomous driving vehicle may be implemented as a mobile robot, a car,a train, a manned/unmanned aerial vehicle (AV), a ship, or the like.

Referring to FIG. 37 , a vehicle or autonomous driving vehicle 100 mayinclude an antenna unit 108, a communication unit 110, a control unit120, a driving unit 140 a, a power supply unit 140 b, a sensor unit 140c, and an autonomous driving unit 140 d. The antenna unit 108 may beconfigured as a part of the communication unit 110. The blocks110/130/140 a to 140 d correspond to the blocks 110/130/140 of FIG. X3 ,respectively.

The communication unit 110 may transmit and receive signals (e.g., dataand control signals) to and from external devices such as othervehicles, BSs (e.g., gNBs and road side units), and servers. The controlunit 120 may perform various operations by controlling elements of thevehicle or the autonomous driving vehicle 100. The control unit 120 mayinclude an Electronic Control Unit (ECU). The driving unit 140 a maycause the vehicle or the autonomous driving vehicle 100 to drive on aroad. The driving unit 140 a may include an engine, a motor, apowertrain, a wheel, a brake, a steering device, etc. The power supplyunit 140 b may supply power to the vehicle or the autonomous drivingvehicle 100 and include a wired/wireless charging circuit, a battery,etc. The sensor unit 140 c may acquire a vehicle state, ambientenvironment information, user information, etc. The sensor unit 140 cmay include an Inertial Measurement Unit (IMU) sensor, a collisionsensor, a wheel sensor, a speed sensor, a slope sensor, a weight sensor,a heading sensor, a position module, a vehicle forward/backward sensor,a battery sensor, a fuel sensor, a tire sensor, a steering sensor, atemperature sensor, a humidity sensor, an ultrasonic sensor, anillumination sensor, a pedal position sensor, etc. The autonomousdriving unit 140 d may implement technology for maintaining a lane onwhich a vehicle is driving, technology for automatically adjustingspeed, such as adaptive cruise control, technology for autonomouslydriving along a determined path, technology for driving by automaticallysetting a path if a destination is set, and the like.

For example, the communication unit 110 may receive map data, trafficinformation data, etc. from an external server. The autonomous drivingunit 140 d may generate an autonomous driving path and a driving planfrom the obtained data. The control unit 120 may control the drivingunit 140 a such that the vehicle or the autonomous driving vehicle 100may move along the autonomous driving path according to the driving plan(e.g., speed/direction control). In the middle of autonomous driving,the communication unit 110 may aperiodically/periodically acquire recenttraffic information data from the external server and acquiresurrounding traffic information data from neighboring vehicles. In themiddle of autonomous driving, the sensor unit 140 c may obtain a vehiclestate and/or surrounding environment information. The autonomous drivingunit 140 d may update the autonomous driving path and the driving planbased on the newly obtained data/information. The communication unit 110may transfer information about a vehicle position, the autonomousdriving path, and/or the driving plan to the external server. Theexternal server may predict traffic information data using AItechnology, etc., based on the information collected from vehicles orautonomous driving vehicles and provide the predicted trafficinformation data to the vehicles or the autonomous driving vehicles.

4.2.5. Example of AR/VR and Vehicle to which Various Embodiments of thePresent Disclosure

FIG. 38 illustrates an exemplary vehicle to which various embodiments ofthe present disclosure are applied. The vehicle may be implemented as atransportation means, a train, an aircraft, a ship, or the like.

Referring to FIG. 38 , a vehicle 100 may include a communication unit110, a control unit 120, a memory unit 130, an I/O unit 140 a, and apositioning unit 140 b. Herein, the blocks 110 to 130/140 a and 140 bcorrespond to blocks 110 to 130/140 of FIG. 35 .

The communication unit 110 may transmit and receive signals (e.g., dataand control signals) to and from external devices such as other vehiclesor BSs. The control unit 120 may perform various operations bycontrolling constituent elements of the vehicle 100. The memory unit 130may store data/parameters/programs/code/commands for supporting variousfunctions of the vehicle 100. The I/O unit 140 a may output an AR/VRobject based on information within the memory unit 130. The I/O unit 140a may include an HUD. The positioning unit 140 b may acquire informationabout the position of the vehicle 100. The position information mayinclude information about an absolute position of the vehicle 100,information about the position of the vehicle 100 within a travelinglane, acceleration information, and information about the position ofthe vehicle 100 from a neighboring vehicle. The positioning unit 140 bmay include a GPS and various sensors.

As an example, the communication unit 110 of the vehicle 100 may receivemap information and traffic information from an external server andstore the received information in the memory unit 130. The positioningunit 140 b may obtain the vehicle position information through the GPSand various sensors and store the obtained information in the memoryunit 130. The control unit 120 may generate a virtual object based onthe map information, traffic information, and vehicle positioninformation and the I/O unit 140 a may display the generated virtualobject in a window in the vehicle (1410 and 1420). The control unit 120may determine whether the vehicle 100 normally drives within a travelinglane, based on the vehicle position information. If the vehicle 100abnormally exits from the traveling lane, the control unit 120 maydisplay a warning on the window in the vehicle through the I/O unit 140a. In addition, the control unit 120 may broadcast a warning messageregarding driving abnormity to neighboring vehicles through thecommunication unit 110. According to situation, the control unit 120 maytransmit the vehicle position information and the information aboutdriving/vehicle abnormality to related organizations.

In summary, various embodiments of the present disclosure may beimplemented through a certain device and/or UE.

For example, the certain device may be any of a BS, a network node, atransmitting UE, a receiving UE, a wireless device, a wirelesscommunication device, a vehicle, a vehicle equipped with an autonomousdriving function, an unmanned aerial vehicle (UAV), an artificialintelligence (AI) module, a robot, an augmented reality (AR) device, avirtual reality (VR) device, and other devices.

For example, a UE may be any of a personal digital assistant (PDA), acellular phone, a personal communication service (PCS) phone, a globalsystem for mobile (GSM) phone, a wideband CDMA (WCDMA) phone, a mobilebroadband system (MBS) phone, a smartphone, and a multi mode-multi band(MM-MB) terminal.

A smartphone refers to a terminal taking the advantages of both a mobilecommunication terminal and a PDA, which is achieved by integrating adata communication function being the function of a PDA, such asscheduling, fax transmission and reception, and Internet connection in amobile communication terminal. Further, an MM-MB terminal refers to aterminal which has a built-in multi-modem chip and thus is operable inall of a portable Internet system and other mobile communication system(e.g., CDMA 2000, WCDMA, and so on).

Alternatively, the UE may be any of a laptop PC, a hand-held PC, atablet PC, an ultrabook, a slate PC, a digital broadcasting terminal, aportable multimedia player (PMP), a navigator, and a wearable devicesuch as a smartwatch, smart glasses, and a head mounted display (HMD).For example, a UAV may be an unmanned aerial vehicle that flies underthe control of a wireless control signal. For example, an HMD may be adisplay device worn around the head. For example, the HMD may be used toimplement AR or VR.

Various embodiments of the present disclosure may be implemented invarious means. For example, various embodiments of the presentdisclosure may be implemented in hardware, firmware, software, or acombination thereof.

In a hardware configuration, the methods according to exemplaryembodiments of the present disclosure may be achieved by one or moreApplication Specific Integrated Circuits (ASICs), Digital SignalProcessors (DSPs), Digital Signal Processing Devices (DSPDs),Programmable Logic Devices (PLDs), Field Programmable Gate Arrays(FPGAs), processors, controllers, microcontrollers, microprocessors,etc.

In a firmware or software configuration, the methods according to thevarious embodiments of the present disclosure may be implemented in theform of a module, a procedure, a function, etc. performing theabove-described functions or operations. A software code may be storedin the memory 50 or 150 and executed by the processor 40 or 140. Thememory is located at the interior or exterior of the processor and maytransmit and receive data to and from the processor via various knownmeans.

Those skilled in the art will appreciate that the various embodiments ofthe present disclosure may be carried out in other specific ways thanthose set forth herein without departing from the spirit and essentialcharacteristics of the various embodiments of the present disclosure.The above embodiments are therefore to be construed in all aspects asillustrative and not restrictive. The scope of the disclosure should bedetermined by the appended claims and their legal equivalents, not bythe above description, and all changes coming within the meaning andequivalency range of the appended claims are intended to be embracedtherein. It is obvious to those skilled in the art that claims that arenot explicitly cited in each other in the appended claims may bepresented in combination as an embodiment of the present disclosure orincluded as a new claim by a subsequent amendment after the applicationis filed.

The various embodiments of present disclosure are applicable to variouswireless access systems including a 3GPP system, and/or a 3GPP2 system.Besides these wireless access systems, the various embodiments of thepresent disclosure are applicable to all technical fields in which thewireless access systems find their applications. Moreover, the proposedmethod can also be applied to mmWave communication using an ultra-highfrequency band.

What is claimed is:
 1. A method performed by a user equipment (UE)configured to operate in a wireless communication system, the methodcomprising: receiving information regarding a plurality of groupsrelated to a plurality of search space sets, wherein the plurality ofgroups comprise a first group with a first group index and a secondgroup with a second group index different from each other; and based onthe second group index being indicated by downlink control information(DCI) being received: after a first predetermined time from the DCIbeing received, monitoring a physical downlink control channel (PDCCH)according to a search space set related to the second group among theplurality of search space sets.
 2. The method of claim 1, wherein thefirst predetermined time is configured as at least one symbol.
 3. Themethod of claim 1, wherein the first predetermined time is configuredbased on a capability of the UE, and wherein information related to thefirst predetermined time is received through a higher layer signal. 4.The method of claim 3, wherein the capability is related to a processingtime required for the UE to change monitoring a PDCCH according to asearch space set related to the first group to monitoring the PDCCHaccording to the search space set related to the second group.
 5. Themethod of claim 1, wherein the information regarding the plurality ofgroups is received through a higher layer signaling.
 6. The method ofclaim 1, based on the second group index being indicated by the DCIbeing received: (i) after the first predetermined time, monitoring thePDCCH according to the search space set related to the second group isstarted, and (ii) monitoring a PDCCH according to a search space setrelated to the first group is ended.
 7. A user equipment (UE) configuredto operate in a wireless communication system, the UE comprising: atransceiver; and at least one processor coupled with the transceiver,wherein the at least one processor is configured to: receive informationregarding a plurality of groups related to a plurality of search spacesets, wherein the plurality of groups comprise a first group with afirst group index and a second group with a second group index differentfrom each other; and based on the second group index being indicated bydownlink control information (DCI) being received: after a firstpredetermined time from the DCI being received, monitor a physicaldownlink control channel (PDCCH) according to a search space set relatedto the second group among the plurality of search space sets.
 8. Amethod performed by a base station (BS) configured to operate in awireless communication system, the method comprising: transmittinginformation regarding a plurality of groups related to a plurality ofsearch space sets, wherein the plurality of groups comprise a firstgroup with a first group index and a second group with a second groupindex different from each other; and based on the second group indexbeing indicated by downlink control information (DCI) being transmitted:after a first predetermined time from the DCI being transmitted,transmitting a physical downlink control channel (PDCCH) according to asearch space set related to the second group among the plurality ofsearch space sets.
 9. A base station (BS) configured to operate in awireless communication system, the BS comprising: a transceiver; and atleast one processor coupled with the transceiver, wherein the at leastone processor is configured to: transmit information regarding aplurality of groups related to a plurality of search space sets, whereinthe plurality of groups comprise a first group with a first group indexand a second group with a second group index different from each other;and based on the second group index being indicated by downlink controlinformation (DCI) being transmitted: after a first predetermined timefrom the DCI being transmitted, transmit a physical downlink controlchannel (PDCCH) according to a search space set related to the secondgroup among the plurality of search space sets.
 10. The method of claim8, wherein the first predetermined time is configured as at least onesymbol.
 11. The method of claim 8, wherein the first predetermined timeis configured based on a capability of a user equipment (UE), andwherein information related to the first predetermined time istransmitted through a higher layer signal.
 12. The method of claim 11,wherein the capability is related to a processing time required for theUE to change monitoring a PDCCH according to a search space set relatedto the first group to monitoring the PDCCH according to the search spaceset related to the second group.
 13. The method of claim 8, wherein theinformation regarding the plurality of groups is transmitted through ahigher layer signaling.